Modeling and acting
Lipton's father arranged her first modeling jobs in New York, while her mother encouraged her to take acting lessons. At 15, Lipton became a Ford Agency model and enjoyed a successful early career. After she and her family moved to Los Angeles in 1964, Lipton signed a contract with Universal Pictures. She made her television debut at age 19 in the NBC sitcom The John Forsythe Show (1965). Between 1965 and 1968, she appeared in episodes of Bewitched, The Virginian, The Invaders, The Road West, The F.B.I., The Alfred Hitchcock Hour, and Mr. Novak.
Lipton starred in The Mod Squad as one of a trio of Los Angeles undercover "hippie cops". Appearing waiflike and vulnerable, as David Hutchings wrote, her performance as "canary with a broken wing" Julie Barnes earned her four Emmy Award nominations and four Golden Globe Award nominations during her tenure. In 1971, she won a Golden Globe Award for Best TV Actress in a Drama. Thin with long, straight, ash blonde hair, clad in mini-skirts, bell bottoms, and love beads, Lipton's Julie Barnes became a fashion icon and the hip "it girl" of her time.
After The Mod Squad, Lipton did no full-time acting for 15 years (with the exception of appearing in the made-for-TV movie The Return of the Mod Squad in 1979). In March 1988, she returned to television as the star of an ABC movie, Addicted to His Love. She eventually regained major attention for her performance as Norma Jennings in David Lynch's TV series Twin Peaks (1990–1991), and subsequently appeared in many TV shows, including recurring roles in Crash and Popular. In 2017 she reprised her character of Norma Jennings in the Twin Peaks revival. Also in 2017, she appeared in an episode of Angie Tribeca as the mother of the title character played by her daughter Rashida Jones.