DeLisle was born in Fort Ord, California, to truck driver George Van Oosbree and singer Joanna Ruth. Her parents separated when she was young. She has one younger brother. DeLisle's mother became a born-again Pentecostal when she was eleven and she was later raised by her maternal grandmother, Eva Flores, a vocalist who performed with salsa musician Tito Puente. She credits her father's love of country music as the biggest influence on her musical taste. She attended Chula Vista High School in the same graduating class as Mario Lopez. In her late teens, she started singing old gospel tunes, and entered the world of comedy on the advice of a friend. In her comedy routine, DeLisle imitated voices. Her impressions earned the attention of a casting director and was advised to take up voice acting. At this time, she went back to her musical ambitions but also took classes in voice-overs. She soon began working with talent agent Sandy Schnarr.