Both Iroh and Aku were voice roles Baldwin inherited from fellow voice actor Mako, who died in 2006.
Baldwin first voiced Aku (from Samurai Jack) in the 2009 video game Cartoon Network Universe: FusionFall. He also voiced Frank Fontaine, the main antagonist in BioShock; though Karl Hanover, who voiced Fontaine's alter ego Atlas in the first game, replaced Baldwin as Fontaine in BioShock 2 and BioShock Infinite: Burial at Sea. His voice can also be heard in numerous other video games, including Tom Clancy's Rainbow Six: Lockdown, Assassin's Creed: Brotherhood, F.E.A.R. and Fallout 4.
Baldwin performed a substantial portion of Splinter's dialogue in the movie TMNT after Mako died during production. In 2016, he appeared as communist Writer Dutch Zwiestrong in Hail, Caesar!
According to an interview with The Dot and Line, Baldwin was able to fill-in for the late Mako Iwamatsu on his voice roles by listening to the cast album of Pacific Overtures, a musical that Mako starred in, which was a personal favorite album of Baldwin’s.
