Sean Patrick Hayes (born June 26, 1970 in Chicago, Illinois) is an American actor.

Trained in the theater in his native Chicago, Hayes moved to Los Angeles in 1995, where he found work as a stand-up comedian. His film debut in the independent film Billy's Hollywood Screen Kiss (1996) brought him to attention, when the film became a success at the Sundance Film Festival.

In 1998, he was cast in the NBC comedy television series Will & Grace, as the constantly unemployed, gay, aspiring actor, Jack McFarland. The show became a hit and Hayes' comedic performance earned him four Emmy Award nominations. He won the Emmy Award for Outstanding Supporting Actor in a Comedy Series in 2001.

His success has led him to film appearances in Cats & Dogs (2001), as Jerry Lewis in Martin and Lewis (2002), Pieces of April (2003), The Cat in the Hat (2003) and Win a Date With Tad Hamilton! (2004).