Iwan was first called in to be the voice of Mickey Mouse shortly after the death of Wayne Allwine on May 18, 2009. Bret first recorded Mickey Mouse dialogue for the Animal Kingdom theme park, as well as the 2009 Disney On Ice: Celebrations, and Disney Live: Rockin´ Road Show.
He gave his first full performance as Mickey Mouse for the English version of the PlayStation Portable game Kingdom Hearts Birth by Sleep and reprised the role in Epic Mickey, Mickey Mouse Clubhouse and Mickey Mousekersize and the English version of the Nintendo DS game Kingdom Hearts Re:Coded.
Iwan´s first voice over work in a Disney park can be heard in the Animal Kingdom closing show, "Adventurers Celebration" as well as on the newly refurbished Tomorrowland Transit Authority ride at the Magic Kingdom, in Walt Disney World, in which upon passing Mickey´s Star Traders, Mickey responds with his signature laugh and ´That´s right, it´s outta this world!´
Bill Iwan, Bret´s father, has an On 2½ model railroad that was featured in the April 2011 Model Railroader