Kym Karath started her career at the age of three, appearing in Spencer's Mountain with Henry Fonda and Veronica Cartwright in 1963 (she would subsequently work with Veronica's younger sister Angela Cartwright in The Sound of Music). Also in 1963, she was seen in The Thrill of It All with Doris Day and James Garner. In 1964, she was seen in Good Neighbor Sam with Jack Lemmon.
Karath graduated from the University of Southern California with a degree in Humanities, and shortly after that she moved to Paris, France where she studied art history and modeled as well. At the age of 26, she married Philippe L'Equilbec; their son, Eric was born in 1991. Thereafter she left acting for a while and lived in Greenwich, Connecticut, before resuming acting in 2005.
After The Sound of Music Kym primarily appeared in American television, including appearances in Family Affair, The Brady Bunch and Lost in Space. She remains friends with the other 'Von Trapp' children today, and in 2000 she went back to Salzburg with them, filming a documentary about the making of the film.
Karath's family was Greek – her original surname was Karathanasis, but it was changed to Karath by her father. She has an older sister, Francie, who auditioned for the eldest Von Trapp child in The Sound of Music, a role that eventually went to Charmian Carr.
She is still currently working with them in new upcoming films. In 2015, she guest judged a "Cake Wars" episode in which Kym Karath also guest judged for "The Sound of Music" 50th anniversary.
