Tae-yeon was born on March 9, 1989 in Jeonju, South Korea. Her family consists of her parents, an older brother and a younger sister.
During her years in middle school, Tae-yeon and her father traveled back and forth from Jeonju to Seoul on every Sunday to receive her vocal training. Jung Sun Won, also known as The One, was Tae-yeon's former vocal instructor. In 2004, he "wanted to acknowledge Tae-yeon's potential" and gave her the chance to be featured in his song "You Bring Me Joy". Subsequently, during the same year, she won the first place at the SM Youth Best Competition and officially received a contract from SM Entertainment. Tae-yeon continued her training under SM Entertainment and debuted as a part of Girls' Generation in 2007. In 2008, Tae-yeon graduated from Jeonju Art High School and was awarded with the school's Lifetime Achievement Award. During her pre-debut days, Tae-yeon was inspired by another artist, BoA. The then-teenager expressed "I have always wanted to be like her and have activities in Japan and around the world" in which that came true when Girls' Generation, after debuting in South Korea, also debuted in Japan in 2010.
"It felt regrettable...that this voice and emotion could be covered up by the title of "idol". - Composer Ahn Young Min
"Through her expressiveness, you feel that she experienced an incredible amount, felt love and went through separations...that feeling existed even during Tae-yeon's school and training days...She expresses emotions very well." - Jonghyun
Over the years, Tae-yeon's vocal ability has received many positive recognition. Park Jin-young once expressed his wish to work with the singer. He emphasized on her strength in expressing emotions and said "Rather than singers who sing well, I like singers [Tae-yeon] who you can't differentiate from singing and talking." Composer Yoo Youngseok, on the other hand, remarked "Tae-yeon feels like a woman who has been divorced seven times", implying that her voice provokes much sadness. Composer Ahn Young Min also expressed, "I was so shocked by Tae-yeon’s singing ability. "I Love You" is a mature song so I was worried, but she made tears fall down my face." Reflecting on her own singing, Tae-yeon stated "When singing, you need performing skills and a bit of imagination. You need to treasure the emotions, and to not deviate from the color of the song while pouring your heart into it."
2007–2009: Girls' Generation debut, solo songs, radio DJ, & We Got Married
Tae-yeon debuted as a member of the South Korean girl group Girls' Generation in July 2007. Being the oldest member, she was selected as the leader of the group. This pressure caused her to sleepwalk for a period of time. Her fellow member Sooyoung expressed "While sleeping, Tae-yeon solves math problems and greets somebody by herself... she also makes phone calls." Tae-yeon later confessed, "It's hard to give out instructions when most of the members are at the same age. I’m also a timid person...during our discussion, the fellow members criticized me..." Despite this however, Tae-yeon still remains as Girls' Generation's true leader, but now all the members participate and she does not have to burden everything alone.
Kim Tae-yeon in 2009
Besides being a part of Girls' Generation, Tae-yeon has also released several songs for various television dramas and movies. Some of them are her solos, while others are collaborations with fellow Girls' Generation members and other artists. In 2008, Tae-yeon released two solo songs, "If" for the KBS2's drama Hong Gil Dong and "Can You Hear Me" for the MBC's Beethoven Virus. The song "If" became popular on various online music charts, while "Can You Hear Me" received the YEPP Popularity Award at the 2008 Golden Disk Awards. Much later, Tae-yeon disclosed "Can You Hear Me" to be her most difficult song to sing, explaining that the introduction requires the lyrics to be delivered as if they are talking, rather than singing. Taeyeon also had a duet titled "7989" with fellow SM artist, Kangta. It was featured on both Girls' Generation's self-titled album Girls' Generation, and Kangta's Eternity. In April, Tae-yeon became a DJ on MBC Radio's program Kangin Taeyeon's Chin Chin Radio, alongside fellow SM artist Super Junior's Kangin. After Kangin left the program in April 2009, it was renamed to Taeyeon's Chin Chin Radio, as Tae-yeon became an independent host and continued on until April 2010. She gained the nickname "DJ Taengoo" while hosting this program.
In 2009, Tae-yeon released the song "It's Love", a duet with Sunny for the MBC's drama Heading to the Ground. The song not only hit the number one spot in various music charts, but also has been hailed as one of the best soundtracks of the latter half of that year. Subsequently, she participated in the song "S.E.O.U.L." (along with Super Junior and Girls' Generation) as an effort to promote tourism for the city of Seoul in South Korea. During the year, Tae-yeon also appeared on MBC's reality-variety show We Got Married and was featured with comedian Jeong Hyeong-don. They played a couple, portraying what life would be like if they were married. When this news was announced on January 7, it caused an uproar among South Korean netizens due to the 11-year age difference between the two.
In January 2010, Tae-yeon became a co-host for the KBS2's idol talk show Win Win alongside 2PM's Wooyoung, Choi Hwa-jung, Kim Shin-young, and Kim Seung-woo. She left the show in August of the same year. On May 7, she had her musical debut as the main female role in Midnight Sun, based on the Japanese novel "Taiyō no uta" by Aya Denkawa. The musical is about Kaoru Amane, a 17-year-old girl, who suffers from Xeroderma pigmentosum, which forbids her from going out during daytime. She keeps her hopes up by writing songs and singing every night at a train station. Tae-yeon received good press for her performance. She also learned to play guitar for her musical performance. Subsequently, when reflecting on her experience, Tae-yeon shared that she found musicals to be difficult, "You have to act and sing at the same time..and you must have a basic sense of concentration...For someone with weaker concentration like me, it was difficult to act like it was the first time no matter how many shows I'd put on." Music-wise, during the year, Tae-yeon released a duet song, "Like A Star", with her mentor The One as well as a solo song, "I Love You", for the SBS's drama Athena: Goddess of War. The former song achieved "all-kill" status through online music charts and the latter also hit some high rankings. In 2011, Tae-yeon had a duet, "Different", with Kim Bum-soo. The song reached number one on some charts not long after it was released. Two years later, the two met again at a Kim Bum-soo's concert, for another collaboration "Man and Woman".
Kim Tae-yeon at the Expo 2012 Yeosu
Previously in 2010, Tae-yeon and her bandmate Seohyun were cast as voice actors for the Korean-dubbed version of the computer-animated film Despicable Me. In 2012, they were recast for Despicable Me 2. Tae-yeon and Seohyun dubbed the voices for the characters Margo and her younger sister, Edith, respectively. Music-wise, Tae-yeon released the single "Missing You Like Crazy" for the MBC's melodrama The King 2 Hearts. The song instantly climbed up to the top of every South Korean chart, and achieved an "all-kill". It was also number one on KBSMusic Bank's OST chart for three weeks. and was eventually picked as the most popular soundtrack of the year at the 2012 Seoul Drama Awards. Tae-yeon also sang "Closer", for the SBS's drama To the Beautiful You. During the same year, Tae-yeon, along with fellow Girls' Generation members Tiffany and Seohyun, formed a subgroup called Girls' Generation-TTS (or TTS), releasing their first mini-album titled Twinkle. The subgroup has a different musical direction and style concept from Girls' Generation, placing their focus on each member's vocal ability while the latter group emphasizes the songs and uniform group performances. The three singers also became the hosts for the MBC's music show Music Core. After hosting for more than a year, they gave their farewell to the show in April 2013, performing TTS's "Goodbye, Hello" as a special stage.
In 2013, Tae-yeon returned to MBC as a one-day guest DJ for Shindong's program, Shimshimtapa, alongside with her bandmate Tiffany. Music-wise, Taeyeon had a duet with Tiffany, "Lost in Love", which was featured in Girls' Generation's fourth Korean album, I Got a Boy. She then released the song "And One" for the SBS's drama That Winter, The Wind Blows. The song debuted at the top of the Billboard Korea K-pop Hot 100 chart and also swept through various other music charts, setting another "all-kill". The song was written and composed by Kangta, expressing the emotions abounding star-crossed love. Subsequently, Tae-yeon lent her voice in the song "Bye" for the movie Mr. Go. It was her first time singing a theme song for a movie.
2014–present: SM The Ballad, Holler & The TaeTiSeo
In February 2014, Taeyeon joined the ballad group SM the Ballad. Being featured in SM the Ballad Vol. 2, she had a duet with Jonghyun for the title track "Breath" as well as a solo song named "Set Me Free". Tae-yeon performed both songs live at the SM The Ballad Joint Recital on February 12. "Breath" was the only track in the album that was being promoted through various music programs in South Korea. It was also the theme song of the Mnet's mini-drama Mimi. In March, Tae-yeon recorded the song "Colorful" for the JTBC's campaign "The World Is More Beautiful Because We're Different". In June, she released "Love, That One Word" for the SBS's drama You're All Surrounded, having the song reaching number two on Melon while topping other music charts as well.
In September, subgroup TTS released their second mini album, Holler. The album debuted as number 1 on Billboard World Albums as well as music charts in several Asian countries. Tae-yeon took the responsibility for the album's song selection. During the promotion period, the three singers was featured in the reality show, The TaeTiSeo. The show took on a more close-up and personal side of the three singers, revealing how they live their normal everyday lives and what they do in their free time. Taeyeon, when expressing her appreciation for fellow Girls' Generation bandmates, stated "If it weren't for such passionate members, I was thinking about how I wouldn't even have had the chance to sing."
In June 2014, Tae-yeon and fellow S.M. artist Baekhyun of EXO were confirmed to have been in a relationship since February.