Connor Paolo attended the Professional Performing Arts School, and later trained at the Lee Strasberg Theater Institute. He began acting when he was nine years old, making his on-screen debut in the film Mystic River, and later snagging a role in the daytime soap One Life to Live. He was also active in regional stage productions.
After earning wide attention with his portrayal of a preteen murderer in an episode of Law & Order, he appeared in films such as Alexander, World Trace Center (which earned him a Young Artist Award nomination) and Snow Angels. In 2007, he joined the cast of the CW's Gossip Girl as Eric van der Woodsen. He played the homosexual character for three seasons before opting to appear in a recurring capacity by season 4. In 2011, Paolo joined the ABC show Revenge as Declan Porter, one of the main cast members of drama series.