Gary Gygax net worth: Gary Gygax was an American game designer and author who had a net worth of $5 million. Gary Gygax was born in Chicago, Illinois in July 1938 and passed away in March 2008. He was best known for co-created the role-playing game Dungeons and Dragons and has been described as the father of the game. Gygax founded the Gen Con gaming convention and created an organization of wargaming clubs. He helped develop the miniatures wargame Chainmail in 1971 and co-founded the company Tactical Studies Rules in 1973. He co-created D&D with Dave Arneson in 1974 and founded the magazine The Dragon. He designed several manuals for the game system and started working on Advanced Dungeons & Dragons in 1977. Gygax licensed the game into the cartoon series in 1983. He would go on to create games like Dangerous Journeys in 1992, the gaming system Lejendary Adventure in 1999, and Castles & Crusades in 2005. Gary Gygax passed away on March 4, 2008 at 69 from an abdominal aortic aneurysm.