Ron Gilbert ca 2017
In 1984 Ron Gilbert was hired at LucasArts (back then Lucasfilm Games) by Noah Falstein1 as a Commodore 64 programmer to port his Koronis Rift game from the Atari 800. While working at the company he learned C and C++ to build the SCUMM compiler (Script Creation Utility for Maniac Mansion), which, as it was game-independent, would be used in his first game and in many games that followed. One reason to create the engine was his experience with the King Quest games that had a parser. Often the parser didn't understand what was typed in, so he thought why not show the verbs. And he wanted to be able to interact with the graphics and to click on things to manipulate.2
About his talent for art he wrote in his blog (Grumpy Gamer); "I have no art talent. None. Absolutely zero. When I try and do art, it destroys nearby things that might also be art. I'm like art anti-matter."
Together with graphic artist Gary Winnick he started in 1985 the development of a game that would become Maniac Mansion.3 Subsequent games he created were Monkey Island I and II, and he was credited for DOTT as one of the writers. He left the company in 1992 to start Humongous Entertainment.
Side note: While he was designing Monkey Island, he wrote an article in The Journal of Computer Design (vol 3 no 2, December 1989) entitled "Why adventure games suck". In the article he proposed a set of rules that in particular minimized the loss of suspension of disbelief in stories and games. As an example to avoid he mentioned "backward puzzle" puzzles, in which the solution (finding a rope) comes before the problem (the crevice).4
Gary Winnick graduated from Monterey Peninsula College with a degree in business and art. He was the co-projectleader and lead artist for Maniac Mansion, and he was credited as writer for the sequel. In 1984 he became the only graphic artist at the newly formed computer division of Lucasfilm. He worked at the company for nine years, first as artist, then as art director and as project leader.
In the beginning the memory of the computer systems made it difficult to design something recognizable in few pixels and colors. But it was hard work and fun working at the new division, and they all ate, slept and breathed computer games.
His credits include the early games like Koronis Rift, and Labyrinth, and later on, besides the Maniac Mansion games, he worked on Zak McKraken and the Alien Mindbenders, Loom, Monkey Island I and II and more recently on the Monkey Island remakes and Thimbleweed Park.
For Maniac Mansion, Gilbert and Winnick wanted to develop a cast of characters and situations that could work together, the more bizarre and strange the better.
Gilbert and Winnick were also involved in many of the early brainstorming sessions of DOTT. According to him, Schafer and Grossman did a great job with DOTT to maintain the integrity of the original characters, concept and feel.5
Tim Schafer worked over a decade at LucasArts. When he studied computer science at UC Berkeley, he became interested in creative writing and started taking classes. At school he saw a job listing for programmers who could write dialog at Lucasfilm Games. In a subsequent interview with LA's David Fox he told him that he loved Ballblaster, who responded that it was the name of a pirated version.
Nevertheless Fox asked him to send in a cover letter with his resume and describing his ideal job (see example here). He was hired in 1989 as a "scummlet" (an assistant designer /programmer), the lowest rung on the totem pole.
He tested some games, and attended "SCUMM University" where Gilbert teached them about SCUMM. Schafer about his experience: "They gave us some old art to work with, so we were just writing goofy stuff and joking around, trying to make each other laugh. I think LucasArts was watching us the whole time, and they picked me (and Grossman) out and said that they liked the writing."6
Later on, when Gilbert had shown him his secret document for a comedy pirate game, he started working with David Grossman (as assistant designer) on what would become Monkey Island I. In the same role he also worked on the sequel, and with Grossman he became co-designer on Maniac Mansion: Day of the Tentacle. Other games he designed for LucasArts were Full Throttle and Grim Fandango.
David Grossman studied Electrical Engineering and Computer Science at Berkeley, where he earned his BS in 1987. About his "breaking in to the games industry" in 1989:
"LucasFilm had a "no death" policy about their games which I was hoping would extend to the job application procedure (...) Somehow, I managed to get in, and then, bafflingly, they hired me".7
He started at LucasArts as co-writer on Monkey Island, and continued as co-writer on the sequel and Maniac Mansion: Day of the Tentacle.
After 15 years, he left the company to join Gilbert at Humongous Entertainment on several point 'n' click games aimed for children, before joining Telltale Games along with a bunch of other ex-Lucasarts guys, where he worked on the new versions of Sam & Max and Monkey Island.
Side note: in an article "Trained to Kill" about a more general subject he also wrote about video games.8 According to him, video games use the same operant conditioning techniques as employed in the military to squelch a soldier's aversion to killing. This conditioning is according to him extraordinarily powerful and frightening. The result is ever more homemade pseudo-sociopaths who kill reflexively and show no remorse.