The group was formed in the mid 1990s as an initiative to address the poor quality of the English localization of Nintendo games during the 8-bits and 16-bits era. The name originates from the localization of Donkey Kong Country where they "locked themselves away" in NOA headquarters while working on the game to keep the game's secrecy and the name held. As the decade progressed, many key members of joined the division, including Bill Trinen, Nate Bihldorff and Tim O'Leary.
Animal Crossing was a critical project for Treehouse as it was the first project where numerous things were changed to localize the game for a Western audience. They kept constant contact with the Japanese development staff.
In 2014, they started to have livestreams on Nintendo games on top of Nintendo Directs, due to the success of their E3 stream.