[5][3][7][8] Kimmel's career began when she was cast to sing the theme song It's Not Just Make Believe for the 2004 Disney live-action film Ella Enchanted.

[6] Kimmel has written, arranged, produced, and performed music which has been licensed in over 650 studio films, network television series, trailers, video games, and commercials.

[10] Notable productions include the films Blockers, World War Z, Southpaw, and The Duff, the television shows America's Funniest Home Videos, The Office, New Girl, Pretty Little Liars, The Lying Game and Grimm, in addition to the Walking Dead trailer.

[14][15] Kimmel has composed 18 theme songs for multiple television series, including Where You Belong for family drama series The Fosters, and has performed tracks in the films Pitch Perfect, Pitch Perfect 2, Dreamgirls, Danny Collins, Descendants, Descendants 2, Teen Beach Movie, Teen Beach Movie 2, and Footloose.

[18] Kimmel has also written songs which have been recorded by notable artists including The Backstreet Boys, Kesha, Joe Jonas, Demi Lovato and Gloria Gaynor.