Graslie was born in Rapid City, South Dakota on June 14, 1989. She earned her bachelor's degree in Studio Art from the University of Montana in 2011. As a part of that program, she interned at the Philip L. Wright Zoological Museum in her senior year. Graslie became a full-time curatorial volunteer after she graduated, while working on her master's degree in museum studies. She cleaned new specimens, gave tours, trained new interns, and acted as a teaching assistant for a class at the University of Montana.
In June 2013, Graslie was hired by Chicago's Field Museum of Natural History to become their 'Chief Curiosity Correspondent'. She continues to host "The Brain Scoop" from this new location.
Graslie first appeared on YouTube in Hank Green's December 7, 2012 VlogBrothers video. In the video, she showed Green a wide variety of the specimens in the lab. Because of her ease in front of the camera, enthusiasm, and fan comments, Graslie was asked to create her own YouTube channel, "The Brain Scoop", as a part of the Nerdfighter family. The series debuted in January 2013. Her work on the series has been described by journalists as "articulate and hilarious" as well as enthusiastic.
Her November 27, 2013 video, which addressed the situation of women in STEM fields and inappropriate comments received to her own postings, received a high level of media attention.