Hexum was born in Englewood, New Jersey, to Gretha and Thorleif Hexum, who were of Norwegian descent.
He and his elder brother, Gunnar, were raised in Tenafly, New Jersey, by their mother after their parents divorced when Hexum was four.
Apparently, he had unloaded all but one (blank) round, spun it, and, apparently simulating Russian roulette with what he thought was a harmless weapon, at p.m., he put the revolver to his right temple and pulled the trigger.
Hexum was apparently unaware that his actions were dangerous.
At the end of the episode, Jack breaks the news that Mac has been killed on the other assignment and would not be coming back.
Hexum's kidneys and corneas were also donated: One cornea went to a 66-year-old man, the other to a young girl.
One of the kidney recipients was a critically ill five-year-old boy, and the other was a 43-year-old grandmother of three who had waited eight years for a kidney.
While working as an apartment cleaner, he met Bob Le Mond of Le Mond/Zetter Management, the manager of John Travolta. At Le Mond's urging, Hexum relocated to Los Angeles in September 1981 to audition for a movie called Summer Lovers, which was to be directed by Randal Kleiser. aired during the 1982–83 television season, with Hexum's role earning him ,000 a week.
Though he lost the part to Peter Gallagher, Hexum attracted the notice of Hollywood powerbrokers, and in short time was cast in the lead role of Phineas Bogg in the NBC series Voyagers! Unable to sustain itself against CBS's newsmagazine, 60 Minutes, Voyagers! Hexum's good looks and charm kept him marketable, however, and he was cast opposite Joan Collins in the made-for-television movie Making of a Male Model, also starring Jeff Conaway and Roxie Roker.