From September 6, 2007 to September 30, 2007, Pelphrey performed in Kevin Mandel's A New Television Arrives Finally as the title character, at Theatre 54, in New York. Pelphrey starred in In God's Hat at the Peter Jay Sharp Theater, in New York City, through August 7, 2010. In 2012, he appeared in the Broadway cast of the musical drama End of the Rainbow as Mickey Deans; in 2015, he returned to Broadway in a revival of Fool for Love, playing Martin.