Article · Wikipedia archive · Last revised Jun 23, 2026

Mike O'Brien (game developer)

Mike O'Brien is an American programmer and video game developer who was the co-founder and former president of ArenaNet, the studio that developed the Guild Wars and Guild Wars 2 MMORPG video games. He led the design and content creation teams of the original Guild Wars.

Last revised
Jun 23, 2026
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Mike O'Brien
OccupationsPresident of ArenaNet (2000–2019)
Programmer at ManaWorks (since 2019)

Mike O'Brien is an American programmer and video game developer who was the co-founder and former president of ArenaNet, the studio that developed the Guild Wars and Guild Wars 2 MMORPG video games.1 He led the design and content creation teams of the original Guild Wars.2

Before co-founding ArenaNet, he worked at Blizzard Entertainment where he worked on Warcraft III: Reign of Chaos3 and was the original creator of Battle.net.4 He also worked on Warcraft II: Tides of Darkness, Diablo and StarCraft, where he, among other things, designed and created the MPQ archives used in all Blizzard games after Diablo. Mike O'Brien was featured as one of the most influential people in the video game industry on PC Gamer's September 1999 cover story "Game Gods".

O'Brien also previously developed an Apple II emulator for Windows, AppleWin, and old DOS ASCII game, Pyro 2.

In 2000, O'Brien left Blizzard to co-found ArenaNet. Among his reasons for leaving Blizzard were the direction of Warcraft 3, and their rejection of an idea of his to turn Battle.net into a third-party game store (similar to Steam, which did not exist yet).5

In early October 2019, through the official Guild Wars 2 news page, O'Brien announced his departure from ArenaNet and his intention to start a new development studio.6 He is currently working as a programmer at the studio "ManaWorks".7

References

References

  1. "Studio Profile – ArenaNet". Edge Magazine: 132–135. September 2011.
  2. Kalning, Kristin (28 March 2007). "'Guild Wars': An experiment that worked". MSNBC. Archived from the original on 10 December 2014. Retrieved 12 August 2010.
  3. "Guild Wars 4th Anniversary Interview". IGN. 23 April 2009. Retrieved 8 June 2026.
  4. Kalning, Kristin (28 March 2007). "'Guild Wars': An experiment that worked". NBC News. Retrieved 8 June 2026.
  5. Wilde, Tyler (8 October 2024). "Oof: Years before Steam, a Blizzard engineer wanted to turn Battle.net into a third-party game store, but was reportedly turned down". PC Gamer. Retrieved 8 June 2026.
  6. "A Message From Mike O'Brien". GuildWars2.com. 3 October 2019. Retrieved 22 April 2020.
  7. "ManaWorks Team". mana.works. Retrieved 17 December 2023.