[1][2][3] Before becoming a successful game designer, he worked as a deputy sheriff, airline agent, and armored car driver[citation needed].

Fannon's career in the gaming industry began in 1988,[4] writing freelance articles and reviews for small-press magazines.

[8] In 1995, Fannon wrote The Fantasy Roleplaying Gamer's Bible, an introduction to the role-playing hobby, for Prima Entertainment.

[15] He also helped DriveThruRPG begin more active support of other charities, leading to them establishing permanent accounts with Hero Initiative, Feeding America, Red Cross, and Doctors Without Borders.

[19] In 2017, Evil Beagle Games became an LLC, with Sean, Bill Keyes, Leonard Pimental, and Michael Surbrook forming the company.

[36] On May 1st, 2018 Christopher Helton posted an article to ENWorld.org detailing accusations made against Sean Patrick Fannon by both named and anonymous sources.

The article detailed allegations including behaviors that made women feel uncomfortable and statements and messages that furthered that sentiment.

[40] On 4 May 2022, Fannon posted on LinkedIn to announce his retirement from full-time professional game development and publishing, saying that he was pursuing "an excellent new career as a technical writer".