Notable for co-founding the Texas-based Id Software video game company, Romero made important contributions to the popular Quake, Doom, Wolfenstein 3D, and Dangerous Dave games.
He created his first video game, Scout Search, in the early 1980s and soon thereafter started a company called Capitol Ideas Software.
He played a key role in popularizing the "first person shooter" video game mode and was the originator of the video game "deathmatch."
He and his third wife, fellow computer software expert Brenda Brathwaite, collaborated on a video game called Ravenwood Fair. His first two marriages resulted in children named Michael, Steven, and Lillia.
He and fellow designer Warren Spector were both involved in the founding of a Dallas gaming company called Ion Storm Inc.