Locke began her acting career at the age of two years. She acted in The Voice of Charlie Pont (ABC, 1962) as Sally Laurents, the daughter of characters played by Robert Redford and Diana Hyland. She went on to play a similar role in 1965 melodrama Once a Thief, as the daughter of Ann-Margret and Alain Delon and niece of Jack Palance, and early the following year played Tootie Smith in the ABC television comedy pilot Meet me in St. Louis.

In the 26-episode ABC television series The Monroes, which screened in 1966 and 1967, Locke, aged six, played Amy Monroe, the youngest of a group of siblings who had to care for themselves in northwestern Wyoming in the Wild West. She was described by the Christian Science Monitor as "an especially endearing little dumpling" for her performance in the series, which was filmed at 20th Century Fox television in Century City, California. Locke was unpredictable and "tumultuous" on set, giving a live frog as a gift to the show's hairdresser. Filming Once a Thief she had objected to a scene where she comforted her wounded, blood-soaked and dying father, on the grounds that, "I've got new clothes on and my mother will be very mad if they get dirty". On one occasion she responded to directorial criticism by pulling on the director's beard.

Locke's final film appearance as a child actor was in Hang 'Em High which starred Clint Eastwood. Her acting work also included television commercials and voiceover recordings. As an adult, she worked as a roller derby skater, radio presenter, and as a singer including with the band The California Express, whose last album was produced by Tex Williams in 1981.