Karen Anita Pendleton was born in Glendale and raised in North Hollywood, California. She was the youngest of three children, with an older sister Yvonne and brother Kent. Her father was a movie set builder, and Karen had no prior exposure to show business before joining the Mickey Mouse Club.
Karen took dancing lessons with Elaine Troy from age three and went to the audition with two other girls from her studio. She was asked to sing, and her slightly raspy voice and wide-open eyes initially made her stand out. She was paired with Johnny Crawford and later with Cubby for duets, and her popularity led to her own mini-series, "Karen in Kartoonland."
Karen appeared in the Disney movie "Westward Ho, the Wagons" and had her own mini-series, "Karen in Kartoonland." She was friends with the other Mouseketeers, particularly the girls her own age, and was given her own segments on the show. However, her screen time decreased as the show shifted focus to the teenage cast members.
After the show ended, Karen's career in show business slowed down. She went on to work as a sales clerk at May department store and later at Prudential. She married Mike DeLaurer, a lawyer and Marine veteran, in 1970, and they had a daughter in 1973. The couple later divorced.
In 1983, Karen was involved in a car accident that left her paralyzed from the waist down. She used this experience as a catalyst to pursue higher education, earning a B.A. and M.S. in Psychology. She worked at a shelter for battered women, testified at government hearings, and served on the Board for the California Association of the Physically Handicapped.
Karen appeared on the Disney Treasures DVD and took part in the 50th Anniversary Celebration for the Mickey Mouse Club. She was awarded a "Mousecar" in 2015 for the MMC's 60th Anniversary, although she did not attend the ceremonies. Karen passed away on October 6, 2019, leaving behind her daughter, son-in-law, and two grandchildren.