Mainframe enlisted in the army airborne at the age of seventeen and soon headed into battle overseas, just in time to get his Combat Infantryman Badge. He left the army to get his degree from MIT on the G.I. Bill then did a stint toiling in the antiseptic corridors of silicon Valley, making big bucks and fighting boredom with a stick. Luckily, the Marines were looking for a few good men with just his qualifications. The proper papers were signed and Mainframe was in uniform. The world's ever-increasing reliance upon technology makes him a valued member of the G.I. Joe team and his ability to design computer viruses makes him a nightmarish nuisance of Cobra.
Mainframe appeared in the original G.I. Joe animated series, voiced by Patrick Pinney. In the G.I. Joe Sunbow cartoon 5-part mini series "Arise Serpentor, Arise!", Beach Head and his teammate Mainframe escaped from Cobra troops by hiding in the actual coffin of Vlad Tepes. When they later escape, Mainframe tells Beach Head he wants to talk to him about his deodorant, in which Beach Head replies: "But I don't wear deoderant." "That's what I want to talk to you about," Mainframe responds. In the same series, Mainframe mentioned a posting he had monitoring base security in Vietnam.
Mainframe was apparently married with children at one point. While driving through Transylvania, he remarks that the countryside reminds him of when he would take his kids trick or treating. In the Sunbow Season 2 episode, "Computer Complications", he mentions having an ex-wife.
In that same episode, Zarana goes undercover at a Joe base as "Carol Weidler". During that time, Mainframe and Zarana develop romantic feelings for each other. At the end of the episode, the Dreadnoks joke to her: "Hey, Zarana, I’ve been thinking! Maybe you oughta quit the Dreadnoks, go marry that wimp, get a house in the suburbs, have kids." to which she responds by shooting in their direction. The episode ends showing both Mainframe and Zarana, miles away looking at the moon, perhaps pondering the same question. In "Grey Hairs & Growing Pains", Zarana helps Mainframe again; he had undergone de-aging.
Mainframe appears in the following episodes:
Arise, Serpentor, Arise
Grey Hairs & Growing Pains
Iceberg Goes South
Last Hour To Doomsday
Let's Play Soldier
My Favorite Things
Into Your Tent I Will Silently Creep
G.I. Joe: The Movie
Mainframe also appeared briefly in the 1987 animated film G.I. Joe the Movie.