He has appeared as a series regular in television sitcoms The Drew Carey Show, American Housewife, and Outsourced, along with notable recurring roles in Better Things and Veep.

He has had a prolific voiceover career, playing characters such as Hoss Delgado in The Grim Adventures of Billy & Mandy, Zeta in The Zeta Project, Tank Evans in the films Surf's Up and Surf's Up 2: WaveMania, Dr. Meridian/Mandroid in Transformers: Earthspark, and provided the voice of Bruce Wayne / Batman in multiple animated films and television series, beginning in 2008 with Batman: The Brave and the Bold.

[2] His patrilineal great-grandfather was Edward L. Bader, who served as the mayor of Atlantic City, New Jersey and is of German and Scottish heritage.

[3] When Bader was two years old, his family moved to Paris, but he returned to the U.S. to attend Groveton High School.

He moved into cinema acting for the 1993 film version of The Beverly Hillbillies, and returned to television, playing Oswald on The Drew Carey Show starting in 1995.

As a voice actor, he has voiced various characters in animated features, television series and video games, such as Ice Age, The Simpsons, Buzz Lightyear of Star Command, The Grim Adventures of Billy & Mandy, South Park and The Penguins of Madagascar.