Mitchell Laurance and his identical twin brother Matthew Laurance appear occasionally together, beginning when they were children in a margarine TV commercial which featured identical twins, and later in an episode of the TV series Cop Rock. Although Matthew was a performer on Saturday Night Live for its sixth season, Mitchell also appeared in uncredited roles on the show for a few seasons (1977–80) and was an associate Director and Producer for the show.

Mitchell appeared on Not Necessarily the News during the 1980s. Other recurring roles were on the TV series, including the very short-lived series Roxie (1987; most of the episodes were unaired), L.A. Law (1987−88), Reasonable Doubts (1992–93), Matlock (1988−95), and Dawson's Creek. Guest roles have ranged from Laverne & Shirley, CHiPs, The Outer Limits, One Tree Hill]], Prison Break, MacGyver, Beauty & The Beast, Empty Nest, and Jake and the Fatman. He was in the "Apollo One" episode of the mini-series From the Earth to the Moon (1998). In the early 1990s he performed the role of Ben Arnold on the soap opera Santa Barbara.

He also has acted in feature films such as Stepfather II, The Runestone, The Hand That Rocks the Cradle, and Urban Mythology, and TV movies (especially in the 1990s) including The Almost Perfect Bank Robbery, Perfect Crime, To Love, Honor and Deceive, Kiss and Tell, Deadly Pursuits, Inflammable, and Death in Small Doses.