Epstein made his Broadway debut in Spider-Man: Turn Off the Dark as the alternate for lead role Peter Parker/Spider-Man. He joined the company on December 4, 2012, and performed Saturday and Sunday matinees, with his first show having taken place on December 8 at the Foxwoods Theatre. Epstein referred to the role as a "childhood fantasy come true." He played his final performance on August 12, 2013, to begin rehearsing for a new musical titled Beautiful: The Carole King Musical, which opened on Broadway on January 12, 2014. This marked his second Broadway show in less than a year. The musical was based on Carole King's life, and Epstein portrayed her former husband Gerry Goffin. He indicated that it was not easy playing the man who broke King's heart. Epstein said, "I'm trying to make his struggle clear, so people understand why he did the things he did. He's not just a villain. I hope people see it's more complicated than that." He remained with the cast until September 21, 2014.