New York Gov. Andrew Cuomo presided over Saturday's nuptials at Joel's Long Island estate, the singer's spokeswoman Claire Mercuri said. The small group of family and friends at the party didn't know the couple planned to exchange vows. Among those in attendance were Alexa Ray Joel, his daughter with his second wife, model Christie Brinkley, and actor Kevin James.
People magazine first reported the wedding.
Joel, 66, and Roderick, 34, have been dating since 2009 and are expecting their first child. Roderick has worked for Morgan Stanley as a risk assessment officer. In 2010, she told the New York Daily News that she met the "Piano Man" at a Long Island restaurant.
Joel has been married three times before -- to Elizabeth Weber Small, Christie Brinkley and Katie Lee.
Joel is currently on tour. On Wednesday, he set a record for most performances by a single artist at Madison Square Garden with his 65th show, besting Elton John.