Lund's early career included minor roles in the 1960s spy film parodies Dr. Goldfoot and the Bikini Machine (1965) and Dimension 5 (1966), as well as the horror film Sting of Death (1965), the beach film Out of Sight (1966), and the western Johnny Tiger (1966). She appeared as a lesbian stripper in the 1967 Frank Sinatra movie Tony Rome, but Lund was so embarrassed by the role that she had her name removed from the credits. Her performance was favorably received and led to a starring role in Irwin Allen's television series Land of the Giants. While waiting for filming to start, Lund was offered the part of Rosemary's friend Terry Gionoffrio in Rosemary's Baby but had to decline when, despite Polanski's assurances, Allen did not believe she would be finished in time.

After Land of the Giants was cancelled, she married co-star Don Matheson, but they were divorced in the late 1970s. Their daughter Michele Matheson is also an Actress. Lund is an alum of Rollins College in Winter Park, Florida.

Valerie in Giantland, a novella written by Lund, is based on the Land of the Giants series, and set ten years later; written from the point of view of Lund's character, Valerie Ames. In 1976, she appeared on the drama General Hospital as Peggy Lowell, the secretary and mistress of Cameron Faulkner, who was played by Lund's husband Don Matheson. Her later films included the Jerry Lewis comedy Hardly Working (1980), Stick (1985) starring Burt Reynolds, and horror movies such as the Christmas horror film Elves (1989) and the comedy Transylvania Twist (1989).

In 1995, she dated Larry King, and the couple were engaged five weeks after they met. The relationship ended before they could marry.