<P> More recently, Hirsch guest - starred on episodes of Warehouse 13, Studio 60 on the Sunset Strip, Law & Order: Special Victims Unit, and The Whole Truth (which saw him reunite with Numb3rs co-star Rob Morrow), among others, and lent his voice to the animated programs Tom Goes to the Mayor and American Dad! In 1999, he reprised his role from Taxi for a brief moment in Man on the Moon, the biopic of his co-star from Taxi, Andy Kaufman (portrayed by Jim Carrey). Judd has also appeared several times on the television show Maron as comedian Marc Maron's father . </P> <P> From 2014 to 2015, he appeared as a series regular on the ABC television series Forever . </P> <P> In 2016 Hirsch appeared on the CBS comedy series The Big Bang Theory portraying Leonard's (Johnny Galecki) father . </P> <P> In February 2017, Hirsch began starring in the CBS comedy Superior Donuts . </P>

Who plays leonards dad on big bang theory
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