(written from a Production point of view)
Diedrich Bader (born 24 December 1966; age 50) played the part of a tactical officer in the Star Trek: The Next Generation second season episode "The Emissary" in 1989. He was credited as Dietrich Bader in the end credits of the episode.
Bader is perhaps best known for his role on The Drew Carey Show as Drew's dim-witted friend Oswald. He also appeared as Jethro in the film version of The Beverly Hillbillies.
He was one of numerous Trek actors to lend his voice to a 3 part of the series Gargoyles. His character was a love interest to a character voiced by Salli Elise Richardson. Others involved in the 3 parter with Bader were Jonathan Frakes, Marina Sirtis, Frank Welker, Cam Clarke, Jeff Bennett, Jim Cummings and Tom Wilson.
Bader made guest appearances on Quantum Leap (with Scott Bakula and Dean Stockwell) and an amusing guest spot on The Fresh Prince of Bel-Air (with James Avery) as a man who marries one of Will Smith's other aunts (though his role was played by another actor in subsequent episodes). He also appeared in the film Office Space with Stephen Root, Paul Willson, and Richard Riehle.
In 1998-1999, Bader along with Robert Stack, Robert Costanzo, Matt Frewer, Samantha Eggar, Jason Alexander, Frank Welker, Corey Burton and Kevin Michael Richardson did recurring voice work for Hercules: The Animated Series.
In 2001-2002, Bader provided the voice for the title character of The Zeta Project. Kurtwood Smith was a regular cast member with some other reccuring voice work being done by Marc Worden, Tara Strong, Grey DeLisle, Javier Grajeda, Marcelo Tubert, Kevin Michael Richardson, Robert Costanzo, Richard McGonagle and Michael Dorn. Other voice actors involved were Earl Boen, Frank Welker, Tom Wilson, Clancy Brown, Hamilton Camp, Tress MacNeille, Dee Bradley Baker, Jennifer Hale, Googy Gress, Larry Cedar, John Rhys-Davies, Chris Demetral, Steven Weber, Neil Ross, Wil Wheaton, Richard Libertini, Nicholas Guest, William Schallert and Michael McKean. Bader and Smith did voice work for an episode of Batman Beyond (which was a crossover with The Zeta Project) along with Keone Young.
He recently provided the voice of Batman on the Cartoon Network series Batman: The Brave and the Bold. Other Trek actors/actresses that have provided voice work in the cartoon include: Dee Bradley Baker, Jason Marsden, Marc Worden, Grey DeLisle, Greg Ellis, Wallace Langham, Kevin Michael Richardson, Loren Lester, Bumper Robinson, Wil Wheaton, Phil Morris, Nicholas Guest, Richard McGonagle, Tara Strong, Armin Shimerman, Michael Dorn, Tony Todd, Stephen Root, Corey Burton, Andy Milder, Tress MacNeille, Ron Perlman, Tara Strong, Julie Newmar and Frank Welker.
In 2014, Bader joined fellow Trek alumni Sufe M. Bradshaw as a recurring actor in the comedy series Veep. In 2015, he received a Screen Actors Guild Award nomination in the category Outstanding Performance by an Ensemble in a Comedy Series for this work.