After writing, editing, and contributing to dozens of books for GURPS, he took on the task of re-designing the entire rule system. He was assisted by David L. Pulver, another Canadian and veteran role-playing game designer. The original design for GURPS is by Steve Jackson.

Sean Punch is currently the Line Editor for GURPS. This is equivalent to being editor-in-chief of a book series, and the key decision-maker for new rules expansions.

He lives in Montréal, Québec.

In an attempt to acknowledge the quality and quantity of his work, some GURPS players have used his online nickname ("Kromm") to create a tongue-in-cheek cult. Steve Jackson Games Forums - So, how great is Kromm anyway? They leave messages in discussion groups pretending to "praise Kromm."

For the Fourth Edition of GURPS

• GURPS Dungeon Fantasy 6: 40 Artifacts (2009)
• GURPS Gun Fu (2009) with Hans-Christian Vortisch and S.A. Fisher
• GURPS Thaumatology: Magical Styles (2009)
• GURPS Action 3: Furious Fists (2009)
• GURPS Action 2: Exploits (2008)
• GURPS Action 1: Heroes (2008)
• GURPS Power-Ups 2: Perks (2008)
• GURPS Power-Ups 1: Imbuments (2008)
• GURPS Dungeon Fantasy 4: Sages (2008)
• GURPS Dungeon Fantasy 3: The Next Level (2008)
• GURPS Dungeon Fantasy 2: Dungeons (2008)
• GURPS Dungeon Fantasy 1: Adventurers (2007)
• GURPS Martial Arts (2007) with Peter Dell'Orto
• GURPS Powers (2005) with Phil Masters

For the Third Edition of GURPS

As sole author

• GURPS Horror GM's Screen (2002)
• GURPS Y2K (1999)
• GURPS Lite (1998)
• GURPS Undead (1998)
• GURPS Wizards (1998)
• GURPS Fantasy Folk, 2nd Ed. (1995)

Compilations and contributions

• GURPS Horror, 3rd Ed. (2002)
• GURPS Low Tech (2001)
• GURPS Monsters (2001)
• GURPS WWII (2001)
• GURPS Steampunk (2000)
• GURPS Bio-Tech (1998)
• GURPS Traveller (1998)
• GURPS Compendium I: Character Creation (1996)
• GURPS Compendium II (1996)
• GURPS Martial Arts, 2nd Ed. (1996)

Sean Punch has appeared in the following newspaper and magazine articles, websites and podcasts.

Podcasts

• RPG Countdown: Sean appeared on these episodes: 18 December 2009 (GURPS Thaumatology: Urban Magics).

Magazine articles

• "The Bigger They Are, The Harder They Fall" in Pyramid #28 (Nov/Dec 1997)