Gary Winnick founded Horizon Zero Graphiques with Frank Cirocco in 1974. There, he was the editor, artist, and writer for the comic magazine Venture, which ran until 1976. Horizon Zero Graphiques also published the comic magazine Mindworks by Brent Anderson, which included art by Gary. He began his video game career at LucasArts as the only artist and animator at the then-newly formed Lucasfilm Games Division in 1984.[4] He worked as an artist and animator on the early games by Lucasfilm Games, before he became co-designer of the 1987 adventure game, Maniac Mansion.[5] He continued working on art and animation at LucasArts, and became the art department supervisor on Indiana Jones and the Last Crusade: The Graphic Adventure in 1989. In 1992, he was the designer, artist, and animator on Defenders of Dynatron City and co-wrote the comic based on the game, with Steve Purcell.[6] Before leaving LucasArts in 1993, he contributed dialog and story to the sequel to Maniac Mansion, Day of the Tentacle. After leaving LucasArts, he joined Spectrum Holobyte as an art director. In 1995, he co-founded the video game company, Orbital Studios, where he served as executive producer. In 1996, he returned as a partner at Horizon Zero Graphiques, which was rebranded Lightsource Studios.
He also co-created the comic book Neomen with Frank Cirocco in 1987 and created the comic book Bad Dreams in 2014. The first issue of Bad Dreams was in the list of the top six new comics and sold out in its first week of release.[7]
Gary Winnick reunited with Ron Gilbert, with whom he co-created his early critically acclaimed point'n'click games for LucasArts, and both of them ran a Kickstarter campaign for a new point'n'click game called Thimbleweed Park. The campaign ended on December 18, 2014 and the game was released on March 30, 2017.[8]