Lockhart was born Anne Kathleen Maloney on September 6, 1953, in New York City, and raised in California. She is the elder of two daughters of Actress June Lockhart and her first husband, Dr. John F. Maloney, and the granddaughter of actors Gene and Kathleen Lockhart. Her great-grandfather was professional concert singer John Coates Lockhart. On December 24, 1986, she married assistant-director Adam Carlyle Taylor, the son of actor Buck Taylor and grandson of actor Dub Taylor. She and Taylor had two children, Carly and Zane. Adam Carlyle Taylor died June 4, 1994, in an accident.

Lockhart began her career at the age of 4, starring as Annie in the short film T is for Tumbleweed, which was nominated for an Academy Award in the category Best Live Action Short Film. She frequently accompanied her mother to the set of Lassie, where she made five uncredited appearances between 1959 and 1962. She began making credited guest appearances in 1965 starting with the Death Valley Days episode "Magic Locket". She has since made over sixty guest appearances in network television shows, including multiple appearances on series such as Knight Rider, Simon & Simon, The Fall Guy, Murder, She Wrote and Diagnosis: Murder. In 1979, she appeared as Lieutenant Sheba in eleven episodes of Battlestar Galactica. She also appeared as Officer Kathy Mulligan in the CHiPs episode "The Return of the Super Cycle", and in the episode "A Dream of Jennifer" on Buck Rogers in the 25th Century.

Lockhart's first film role was playing Dora in the 1973 western Jory. That same year, she appeared in the critically acclaimed Hallmark Hall of Fame episode Lisa, Bright and Dark, alongside Kay Lenz, Anne Baxter and John Forsythe. She then appeared in the films Sunburst (1975) and Joyride (1977), with Robert Carradine and Melanie Griffith. She played the young Eunice St. Clair in the 1986 horror film Troll, with her mother playing the older version of her character. Her other film credits include Just Tell Me You Love Me (1978), Hambone and Hillie (1983), Young Warriors (1983), The Oasis (1984), The Serpent Warriors (1985), Dark Tower (1989), Big Bad John (1990), Bug Buster (1998), A Dog's Tale (1999), Daybreak (2000), Cahoots (2001), Hollywood, It's a Dog's Life (2004), ExTerminators (2009) and Dakota's Summer (2014).

Though Lockhart herself claims no recollection of being approached, she was reportedly John Carpenter's first choice to play the role of main character Laurie Strode in Halloween (1978). Other commitments kept her from doing so.

In 1980, she appeared in a Magnum PI episode "Lest We Forget" playing a World War II flashback version of character Diane Westmore played by her mother June Lockhart. Through the 1980s and '90s, Lockart appeared steadily in a variety of credited and uncredited roles primarily on television series.

In addition to her television and film appearances, Lockhart has also worked extensively in commercials and voice acting. In 1997, she began working with Lane Davies to form the Kingsmen Shakespeare Festival, the forerunner of the Kingsmen Shakespeare Company, which offers seminars and summer camps aimed at teaching children ages 8–16 various acting techniques. Lockhart is currently a member of the Board of Directors.

In the 2000s and 2010s, Lockart had several reccurring and multi-episode minor roles on series such as The Lying Game, Dragnet, The West Wing, NCIS, the Law & Order franchise shows, and Chicago Fire. These roles were often "uncredited" and as a "policewoman". She also had similar one-time roles on shows such as Studio 60 on the Sunset Strip, Raines, and Chase.