Jenner was born January 14, 1941, in Philadelphia, Pennsylvania. He began acting during his college years at West Chester University, in Pennsylvania. After graduation, Jenner moved to New York City where he found roles in Club Champion’s "Widow," opposite Maureen Stapleton, and "Put Them All Together" with Mariette Hartley. Along with Olympia Dukakis, he was a founding member of the innovative Whole Theatre Company where they starred together in "Long Day’s Journey Into Night." Jenner also received wide acclaim as the self-destructive pitcher in Jonathan Reynolds' hit play, "Yanks 3, Detroit 0, Top of the Ninth," directed by Alan Arkin at New York City’s American Place Theatre.
His early television roles included two daytime soap operas. He played Tony Cooper on Somerset (1974–1976) and Evan Webster on Another World (1976–1978), where he was involved with Olive Gordon (Jennifer Leak) in an infamous storyline plot to kill long-time character John Randolph. Jenner married Another World co-star Susan Harney (Alice Matthews Frame) on May 23, 1980, but the couple later divorced. In 1985, Jenner played Matt MacKenzie on Days of our Lives.
In 1981, Jenner appeared in several episodes of Knots Landing as Jeff Cunningham, Abby's (Donna Mills) ex-husband. He later had a recurring role as Dr. Jerry Kenderson on Dallas (1984–1986).
Jenner portrayed Starfleet Admiral William Ross in 12 episodes of Star Trek: Deep Space Nine from 1997-99. He was also known for his role on the hit sitcom Family Matters, using comedic talents in the role of Lieutenant Murtaugh.
Jenner's other TV credits included Hart to Hart, Simon & Simon, St. Elsewhere, JAG, Super Password and $10,000 Pyramid.
In addition to his wife, Jenner is also survived by his stepsons, Ashley and Christian.