Jim McMullan figured he'd be an architect. He earned a degree in architecture in 1961 and considered joining the Peace Corps. But an audition Sam Peckinpah's 1962 film Ride the High Country led a significant shift in careers. He did not land a role in that Western, but Universal signed him to a contract.

That deal with the studio led to roles on Wagon Train, The Virginian and Alfred Hitchcock Presents. He continued to land small parts on television throughout the Sixties. Meanwhile, McMullan scored a couple of significant film parts, alongside two Hollywood legends. In 1965, McMullan portrayed on of the sons of Jimmy Stewart in Shenandoah. Four years later, he was skiing down slopes alongside Robert Redford in the winter sports drama Downhill Racer.

That heightened profile snowballed into two lead roles on television. In 1974, McMullan acted alongside Dirk Benedict in Chopper One, a police helicopter procedural. Alas, that Aaron Spelling production had difficulty staying in the air. Benedict would later land in a role in Battlestar Galactica. McMullan nabbed the lead part in another sci-fi adventure, 1980's Beyond Westword, a sequel series to the hit movie. Despite earning two Emmy nominations, Beyond Westworld lasted a mere handful of episodes.

The Everett CollectionJim McMullan with Connie Sellecca in 'Beyond Westworld'

From 1986–87, McMullan appeared in a recurring role on Dallas as Senator Andrew Dowling, the love interest of Donna Culver (Susan Howard).

McMullan continued to rack up roles on television on series such as Baywatch, MacGyver, Santa Barbara and Doogie Howser. 

His lengthy resume featured dozens of TV parts. Notably, he was a favorite of Quinn Martin. The superproducer cast McMullan on The F.B.I., 12 O'Clock High, Barnaby Jones, Cannon and The Streets of San Francisco.

On May 31, McMullan passed away from complications due to ALS, according to The Hollywood Reporter. He was 82.