Lesley-Marie Colburn grew up across the street from Groucho Marx in Beverly Hills. Her paternal uncle, Sol M. Wurtzel, was a Hollywood film producer and one-time VP of the Fox Film Corporation. He was instrumental in getting his niece cast in her first film in an uncredited role as early as 1952 and ensuring she was seen by producer extraordinaire Cecil B. DeMille. Her maternal uncle, Mel Berns, was head of makeup at RKO Studios, and often made her up, for roles at RKO.

Her father, Sid Colburn, was a haberdasher/clothier to the stars in Beverly Hills, and she worked under her own name Lesley-Marie Colburn, but was formerly known at the Hollywood Professional School as Marie Behar, having adopted her mother's maiden name after her parents' divorce, and because her mother was Madame Behar, the French Instructor at the Hollywood Professional School.