Karla Cheatham Mosley was born in Susquehanna Depot and raised in Westchester, New York. She graduated from New York University's Tisch School of the Arts, with honors, and went on to study in France at the Roy Hart Vocal Institute.
At a young age, Mosley performed in Sugar Beats, a children's rock group, where she sang such hits as "Rockin' Robin".
In 2003, while still in college, Mosley joined the American counterpart of the Australian children's TV show Hi-5, where she became the youngest member of the group. Her segment was called "Body Move", where she led viewers in stretching, exercising, and silly dances. She was usually the transitional member of the group, performing her skits in between other cast members' acts. She also provided the voice of Chatterbox on the show. She was the American counterpart of Charli Robinson.
In 2006, Mosley left the cast of Hi-5 in order to pursue other interests.
Mosley played the role of Christina Moore Boudreau on the now defunct soap opera Guiding Light. Christina is a pre-med student who married Remy Boudreau (played by Lawrence Saint-Victor).
In 2013, Mosley joined the cast of The Bold and the Beautiful as ex-con turned actress Maya Avant. Karla completed a website series titled Room 8 The Series with her co-star from The Bold and the Beautiful, Lawrence Saint-Victor. The web series was part of the B&B storyline. Karla's character has recently been revealed to be a transgender woman. In 2015 Karla's character became the first transgender bride to be married on daytime television when she married Rick Forrester (played by Jacob Young).
Mosley also appears in many local New York City venues (including for a time as the featured performer for the Gray Line Show Business Insider Tour), sometimes as singer, sometimes actor.
In 2007, Mosley starred in the musical production of Dreamgirls at the TUTS Theater in Houston, TX.
Mosley appeared in the children's off-Broadway production, Max and Ruby in 2007–2008.
Additionally, she had a part in the Coen Brothers film, Burn After Reading, which opened in September 2008.
Mosley will also be seen in the indy film, Red Hook.
In 2008, Mosley starred with Lenelle Moise in "Expatriate", a gritty off-Broadway show at the Culture Project. Her performance earned rave reviews from the New York Times, Time Out New York and Variety, which wrote: "Mosley's voice is a serious discovery, with remarkable phrasing and range. In a torchy number called 'The Makings,' about how Alphine's life has given her the makings of a jazz legend, her pure high notes descend to earthy growls in a flash, and you've got to believe her when she sings, 'Anything I wails/hits ears like honey.'" In 2008 she also nabbed parts in Law & Order and Gossip Girl and appeared in Museum Pieces at the West End Theater in New York City.
In 2013, Mosley appeared in several episodes of Hart of Dixie.
Mosley also appeared in commercials sponsoring Abreva and Riders by Lee jeans.
On November 18, 2014, Karla appeared as a model on The Price Is Right.
She appeared in the 6th episode of Battle Creek on April 5, 2015, titled "Cereal Killer".
Karla Mosley sits on the board of Covenant House, the largest privately funded agency in the Americas providing shelter and other services to homeless, runaway and throwaway youth. She is a celebrity ambassador for the National Eating Disorders Association and is active in other charities.
After Hurricane Katrina, Mosley organized a benefit concert by Hi-5 to raise money for victims of Hurricane Katrina. She co-produced and performed in Broadway for Obama, a benefit concert during the 2008 presidential campaign. She also performed in Broadway for a New America's concert for marriage equality and in Western Queens for Marriage Equality's rally for equality.
Mosley has one sister and two cats. She is married to Jeremiah Frei-Pearson.