Fierstein will play a liberal judge who presides over a case on which Julianna Margulies' character Alicia is working.
Arden has been cast in the recurring role of a philosophy professor who will be a romantic interest for Dallas Roberts' character, Owen.
Fierstein has won Tony Awards for his performances in Hairspray and Torch Song Trilogy, for which he also received a Best Play Tony. In addition, he won a Tony Award for his book for the musical La Cage Aux Folles. His film and television credits include Independence Day, Playing Mona Lisa, How I Met Your Mother, and The Big C.
Arden's Broadway credits include Big River and The Times They Are A'Changin', and he also starred Off-Broadway in bare. Among his other television credits are Kings, The Closer, and Bones.