The actor will recur as Scott Welker, the artistic director of a theater company who has history with a couple of the characters. Will he clash with Julia's (Debra Messing) reported new love interest, played by Daniel Sunjata?
Besides Law & Order, Martin has also starred in several Broadway shows, including the original production of Rent. He joins previously announced Smash guest stars Jennifer Hudson and Sean Hayes.
Smash returns midseason on NBC.