The first season originally aired from September 24, 2013, to May 13, 2014, while a second season began airing on September 23, 2014. After initially high ratings but mixed reviews, ratings steadily dropped, while reviews steadily improved, throughout the first season. This led to much lower but more consistent ratings, as well as more positive reviews, in the second season.
Reprising his role from the MCU filmsIron Man, Iron Man 2, Thor, and Marvel's The Avengers, and the Marvel One-Shot short films The Consultant and A Funny Thing Happened on the Way to Thor's Hammer, Gregg headlines the series, and has appeared in every episode. He was the first principal actor cast in the series. Speaking of his character's resurrection after dying in The Avengers, Gregg said, "the mystery and the complexity and the unanswered questions about Phil Coulson standing there trying to deal with this, I found it so fascinating and so true to the world of the comics and mythology in general as I understand them that I was immediately in".
Originally listed with the name Agent Althea Rice on casting sheets, Melinda May was created by Joss Whedon, who "has had [the character] rolling around in his head". Wen was cast in the role in October 2012. In preparation for the role, Wen was "given a couple of background stories about her", but found it challenging to play a character who is respected by those around her, even though the audience doesn't know why, stating "It's a challenge in different ways. I think, at this point, I really am starting to know who she is and the stuff that I use to help me understand what could have happened to her to have brought her out of the field and into a desk job, I think we've all pretty much experienced that. So I use some of my own personal experience where we've been scarred or we've been greatly disappointed".
"Relative newcomer" Dalton was cast as Ward in November 2012. Talking about creating an original character, Dalton said "In some ways, originating gives you a kind of freedom because there's not volumes of comic books behind you that you need to live up to." On working with the showrunners he said, "They're really good at what they do. It feels like how real human beings talk. Also real human beings who have a sense of humor and a sense of humanity and heart. I had a feel for it as soon as I read it. I felt like okay, this is a full character. Because of Marvel's super secrecy, we only had like three pages to read. We didn't have a full script, but I felt like there was a full character there on the page. From the very beginning I thought I get this, I get this world and I'd really like to be a part of it."
In December 2012, Bennet became the final primary cast member for the first season. Concerning Joss Whedon's tendency for writing strong female characters, Bennet said, "The best part about Joss casting and writing these sharp female roles is that he doesn't think it's a big deal, because it shouldn't be a big deal. The media attacks out when people write strong male roles, so why isn't something like that talked about when [there are] female roles. To him that's just obvious that it should be done, and that's what I love about it the most." Responding to a comparison between her character, Buffy, Faith, and Willow, Bennet said, "I get that a lot! I guess people see the similarities, but I like to think that she is her own character and is going to be even more so coming up through the season, because it does get pretty crazy." In December 2014, Skye's true identity was revealed to be Daisy Johnson, an Inhuman in the MCU.
De Caestecker was cast in November 2012, and later said that "Fitz has got this funny kind of temper. He's quite passionate about what he does. So those moments where – I don't think he's someone that really responds very quickly to emotion; he doesn't really understand emotions as much, so when you do see that kind of side to him, I think it's quite interesting." Fitz has a lot of interaction with Simmons in the series, with De Caestecker explaining "My character, he's Engineering, so he's on the computer and tech side of everything. He's consumed within that world, and he works very closely with Simmons, who's Biochem. They've got this kind of weird chemistry together, and they just kind of fit each other in a very weird way."
Henstridge was also cast in November 2012, describing her character as "a biochem expert. She's young and hungry and she's a great woman to play because she's intelligent and focused and curious and she doesn't apologize for it. She's got a wonderful relationship with Fitz. They kind of bounce off each other." She also talked about the characters being separated, saying "That's interesting because then you see that they've never been without each other. When you see them without each other, that brings a whole new dynamic just to them as characters in discovering what it's like to have to be independent because this whole S.H.I.E.L.D. team has come together and everybody is on their own apart from Fitz-Simmons. We will get to see that and it's quite funny."
Blood was announced as cast in the second season at the 2014 San Diego Comic Con, and in September 2014, he was confirmed to be a member of the principal cast for the season. The character was a mercenary, then decides to become a S.H.I.E.L.D. agent.
In August 2012, ABC ordered a pilot for a series called S.H.I.E.L.D. to be written and directed by Joss Whedon, with Jed Whedon and Maurissa Tancharoen also writing. Disney CEO Bob Iger greenlit the series after watching the Marvel One-Shot short film Item 47. In April 2013, ABC announced that the series would be titled Marvel's Agents of S.H.I.E.L.D., and it was officially picked up for a full season in May 2013, with a second season renewal coming in May 2014.
The people who are ignored are the people I've been writing as my heroes from day one. With S.H.I.E.L.D., the idea of [Agent Coulson] as the long-suffering bureaucrat who deals with Tony Stark's insufferability is delightful and hits the core of something I'm also writing about all the time—the little guy versus the big faceless organization. Now, somebody might point out, "But isn’t S.H.I.E.L.D. a big faceless organization?" It absolutely is, and that’s something we’re going to deal with in the series. But what's really interesting to me is there’s a world of super-heroes and superstars, they're celebrities, and that's a complicated world—particularly complicated for people who don't have the superpowers, the disenfranchised. Now, obviously there's going to be high jinks and hilarity and sex and gadgets and all the things that made people buy the comics. But that's what the show really is about to me, and that's what Clark Gregg embodies: the Everyman.
—Joss Whedon on the underlying themes of the series.
Jed Whedon, Tancharoen, and Jeffrey Bell act as the series' showrunners, and supervise all creative decisions, with Joss Whedon having assisted them before he started work on Avengers: Age of Ultron. Bell explained the writing process, saying "While one person is writing a script, I can have two of us break other stories so I can have, in theory, a story broken every couple of weeks. That’s the only way we can get ahead of the production train, because we shoot a new episode every eight days. If there’s a story that I, Jed and Maurissa like we say ‘Yes,’ that writer goes off and writes their outline, we give them notes, they write a script and then we send this to network and get their notes, then get production feedback on what we can and cannot do, that writer then goes off and is on set producing the episode".
In January 2013, Joss Whedon deflected any direct influences from other series, such as the efforts of Fox Mulder and Dana Scully in The X-Files, and explained that while the show would involve people with powers and the spectacle of science-fiction storytelling, it would focus on "the peripheral people ... the people on the edges of the grand adventures." On what he learnt from making previous series, Whedon said, "Have a different reason to tell a story every week and not just have a different story. This is the hardest thing, because S.H.I.E.L.D. doesn’t lend itself to the same level of absurdity; it’s a more straightforward show. I want these stories to connect to the people who are solving them. That won’t always be the case; sometimes it will be a cool story with character stuff that resonates, and that’s not bad, but I want more than that."
On the balance between creating new material and drawing from existing mythology, Bell said "The challenge from the get-go was telling stories that non-Marvel fans will understand and enjoy, while entertaining all the Marvel fans. There are a few ways we're trying to do that. If we can tie something in from the movies, whether it's Chitauri or [Samuel L. Jackson's "0-8-4"] cameo, which was a cool thing; or whether it's fallout from the battle of New York — specific Marvel movie stuff — that's fun, and we try and do that in a way that everyone would understand. Then we also try and mine the Marvel comic universe. If we're looking for a doctor, we might say, "Is there a doctor in the Marvel Universe, who would be fun if the fans hear that character's name? Can we make it that person and bring that quality to it? Is there a weapon or a cool tech thing from that universe that we could use that is cool on its own, but if you're a Marvel fan, you go, 'Oh my god, they did that!'" So we're trying to do it that way." On where the series can draw from the comics, Jed Whedon said, "There are obviously areas that we can go, but we have to dabble and there are some places we can’t go ... It’s more of an inspiration as far as generating story." Tancharoen elaborated that, "We’re always going to be inspired and influenced by the comics, but of course on the show, we’ll always be doing our spin to it."
About comparisons between the scope of the series and that of the films, Bell said "Both ABC and Marvel have been very generous with our budget. For a network TV show, I can't complain ... And yet, even a show like Game of Thrones is more than double our budget, so even on TV, we're competing against shows with giant effects ... You want those Marvel moments. You want the cool weapon, you want the cool holographic display. At the same time, the way TV lives and breathes is with characters ... Our long game is that you'll care about them. We'll always have the cool Marvel stuff, and we'll always have as much scope and scale as we can afford, but that's still only about 10 minutes of Iron Man, y'know? The stuff you remember in Avengers is the character stuff. There was a giant, cool action scene at the end with the Chitauri invading and giant flying things, but when you ask people what their favorite part of the movie was, it's "When Banner and Stark were talking in the lab, that was cool," or "When Hulk used Loki as a ragdoll. That was funny." It's always the character moments that stay with people, and that's something TV does really well". Jed Whedon elaborated that "We get to the point of, What do we need for the story to be told, and how can we change these sequences to be from the point of view of the characters? That’s something we talk about a lot. If a monster is landing on a car, instead of showing the whole monster leaping through the skyline, we want to be in the car with the character having that experience. It works for our show, but also on a budgetary and time level. It helps us avoid these big effects by personalizing them and making them more visceral."
Following Samuel L. Jackson's cameo in an 'end tag' at the end of "0-8-4", Bell explained that "Part of our storytelling on this show is going to be a tag every week. We need people to know about that. The show ends, the S.H.I.E.L.D. eagle comes up, there are nine hours of commercials because it's TV, and then before we go to the next show, we're almost always going to have another minute, minute and a half of something, and those will be different from week to week. One of the things we want people to know is, "Stick around for the tag." Having a special one like [Jackson's cameo] early is also to tell you, "Pay attention to that." I know when "Iron Man" did that after all the credits, a lot of the people left and didn't know they should have stayed. Now you watch a Marvel movie, and everybody stays until the end. We're going to be doing that, and we want people to know. Sometimes it'll be funny, sometimes it'll be a mythology thing, sometimes it'll be a self-contained thing, or an extra little reveal about something that was in the episode."
Marvel Cinematic Universe tie-ins
Marvel is complicated in that we’re part of the Marvel Cinematic Universe, and so after [running something by Jeph] Loeb we’ll run it through New York, Joe Quesada, Dan Buckley and those guys. We pitch our stuff to Kevin Feige and his movie group to see if there’s something we can tie into, to see if they’re okay about us using a character, or a weapon or some other cool thing. Everything is interconnected, and that’s really what we have to pay the most attention to. It’s challenging but fun as we try to lace some Easter egg in, something that ties into a movie or, if not, at least the comics so fans can find those little things that nobody else knows about.
—Agents of S.H.I.E.L.D. executive producer Jeffrey Bell in September 2014, explaining the process of working in with the MCU
In July 2013, Jed Whedon said the series will work in tandem with the Marvel films, both past and upcoming, saying, “We plan on trying to weave in between the films and try to make them more rewarding on both ends.” In March 2014, the producers stated at the show's PaleyFest panel that they and the writers are able to read the screenplays for upcoming MCU films to know where the universe is heading, which allowed them to form a general plan for the show through the end of a third season, should the show be renewed for such.
Jed Whedon later explained that, "The idea with every Marvel property is for them to exist on their own and then interweave. No one backswipes; Thor didn’t show up in Iron Man 3. It’s not that these things are dependent on one another. They had the opportunity to interact and they exist in the same universe and we are in the same universe and when we establish something in our universe, in our show, it becomes a rule in the universe so we have to make sure we’re respectful of what they’re planning to do and that we’re all on the same page." Elaborating, Bell said, "If you look at all the Marvel movies, there are only a couple of superheroes ... For us to have powers every week kind of explodes their movie universe in a way we didn't want to do. Finding occasional characters who are superheroes -- and whether that's someone new like Mike Peterson in the pilot, or whether later on there are a couple of places when people hear the name, that will be meaningful to the Marvel fans. But we have to be judicious, otherwise we've got 20-some new superheroes running around at the end of the first season, and suddenly [Avengers: Age of Ultron] is a very different movie."
The episode "T.A.H.I.T.I." introduces the alien race the Kree to the MCU, members of which play a significant role in the 2014 film Guardians of the Galaxy. This begins a storyline that recurs throughout the series, and introduces the Inhumans to the MCU.
The series has been licensed in 155 countries and territories.CTV announced in June 2013 that they hold the broadcast rights for Canada. On August 22, 2013, it was confirmed that Channel 4 would air the show in the United Kingdom. In Australia, the show airs on Channel 7.
Social media accounts for the series were set up in January 2013, months before ABC officially ordered it, "a rarity for a pilot". By May 17, 2013, the series was the top new show of the television season in terms of social media activity, with the series' official Twitter account having over 46 000 followers and its official Facebook page having close to half a million likes at the time. Social media was used throughout the season, with many cast members live tweeting each episode. On using social media to interact with the fans, J. August Richards said "In the Angel days, all there was, was a community that was like a chat room. If you were looking for feedback, you had to look for it. Now, the feedback comes right to your phone, which is really interesting. I was live tweeting the pilot, and ... I got to watch the arc in real time. To watch the audience take that journey".
The complete first season was released on September 9, 2014, on Blu-ray and DVD. Bonus features include behind-the-scenes featurettes, audio commentary, deleted scenes, a blooper reel, as well as the television special, Marvel Studios: Assembling a Universe.
In the United States, the premiere episode of Agents of S.H.I.E.L.D. earned a 4.7/14 rating in the 18–49 year old demographic, with 12.12 million total viewers, making it the biggest network drama debut in four years. Though the series debuted to strong ratings against its competition, NCIS, its ratings declined considerably over the following two months, though it remained Tuesday's top show among men 18–49, and overall was the No. 3 show among upscale young adults behind Modern Family and The Big Bang Theory. It also enjoyed DVR recordings that, according to TV Guide, were "through the roof".
The review aggregator website Rotten Tomatoes reported an 86% approval rating with an average rating of 8/10 based on 43 reviews. The website's consensus reads, "Marvel's Agents of S.H.I.E.L.D. is sure to please comic book fans, but the strong ensemble and brisk pacing help to make this better-than-average superhero show accessible to non-fanboys as well."Metacritic, which uses a weighted average, assigned a score of 74 out of 100 based on 33 reviews, indicating "generally favorable reviews." The second season has received more positive critical reception than the first season, and scored a 92% approval rating on Rotten Tomatoes. The website's consensus reads, "Marvel's Agents of S.H.I.E.L.D. relaxes into itself during its sophomore season, mitigating the show's growing pains by focusing on characters while amping up narrative thrills."
Mary McNamara of the Los Angeles Times felt that the series "created a whole new sort of television show: One that must support, and change with, the plot twists of its film family ... never before has television been literally married to film, charged with filling in the back story and creating the connective tissue of an ongoing film franchise." She stated that the crossover "infused S.H.I.E.L.D. with a new energy, and helped explain, perhaps, why the show took so long to find its footing — in the writers' room at least ... That Agents of S.H.I.E.L.D. was able to succeed as a story both independent and ancillary is all but miraculous." She concluded that the series "is now not only a very good show in its own right, it's part of Marvel's multiplatform city-state. It faces a future of perpetual re-invention, and that puts it in the exhilarating first car of television's roller-coaster ride toward possible world domination."
In July 2014 at San Diego Comic Con International, Marvel Comics announced an ongoing series titled S.H.I.E.L.D., to be set in the mainstream Marvel Universe, and written by Mark Waid, beginning December 2014. Art will be by a rotating group of artists including Carlos Pacheco, Alan Davis, and Chris Sprouse. The series is led by Agent Phil Coulson, and will see the canonical introduction of characters that originated from the television series, to which Waid said, "This is our chance to introduce a lot of the other characters into the Marvel Universe, and give them the Marvel Universe spin." Waid described the series as "done-in-one. Coulson and his team have a mission, and if we need someone for a mission, everyone in the Marvel Universe is available as a potential Agent."