Kevin Sussman (born December 4, 1970) is an American actor and comedian. He played Walter on the ABC comedy-drama Ugly Betty and Stuart Bloom on the CBS sitcom The Big Bang Theory. Starting with the sixth season of The Big Bang Theory, he was promoted to a series regular.
Sussman is one of four brothers born to Jewish parents. He grew up in Staten Island, New York City, New York where he attended Staten Island Technical High School and graduated from New Dorp High School.
He attended the College of Staten Island for a year but graduated from the American Academy of Dramatic Arts in Manhattan, New York City. He later studied with acting teacher Uta Hagen for four years.
Sussman's professional acting began in commercials, playing geeks or nerds, like a young Eddie Deezen during the dot-com boom for companies such as FedEx. At the time, he worked as a computer consultant.
In 1999, he made his film debut in Liberty Heights as Alan Joseph Zuckerman. Sussman moved to Los Angeles when he was cast in Ugly Betty. He played the character Stuart Bloom on The Big Bang Theory from 2009 to the series end in May 2019.
In 2011 and 2012, he worked with The Big Bang Theory co-star John Ross Bowie to create two television comedies: The Ever After Part (FOX) and The Second Coming of Rob (CBS).
On July 9, 2025, it was announced that Sussman would star in a spin-off series Stuart Fails to Save the Universe to be streamed on HBO Max. The show also stars Lauren Lapkus and Brian Posehn.
Sussman was married to Alessandra Young from 2006 until 2017.
Sussman married Addie Hall in April 2023.