While still performing as Cupid, Foa began the audition process for Broadway's Avenue Q. After two months, five auditions, and a lot of puppet practice, he became an understudy to the roles of Princeton/Rod in December 2003. After the show had run for about a year, Foa was promoted and began to perform the lead role on February 1, 2005. He continued in the lead role for a year and a half. While performing in Avenue Q, Foa was offered the role of Leaf Coneybear in the Broadway musical The 25th Annual Putnam County Spelling Bee. For two weeks he rehearsed for Spelling Bee during the day and performed Avenue Q in the evening. His stint as Leaf Coneybear lasted from July 11, 2006 until April 15, 2007.