I Love You, Man Cast

Paul Rudd plays Peter Klaven, a real estate agent who searches for a male friend to be his best man.

Jason Segel portrays Sydney Fife, an outgoing man who becomes Peter's friend and helps him navigate his social life.

Rashida Jones plays Zooey Rice, Peter's supportive fiancé who encourages him to find a close male friend.

Andy Samberg appears as Robbie Klaven, Peter’s younger brother who has a humorous outlook on relationships.

J.K. Simmons plays Oswald Klaven, Peter and Robbie's father who shares his own experiences with friendships.

Jane Curtin portrays Joyce Klaven, Peter's mother who is both caring and comedic.

Jon Favreau plays Barry, a friend of Peter who has a casual and laid-back attitude.

Jaime Pressly appears as Denise, a confident and direct character in Peter's social circle.

Rob Huebel portrays Tevin Downey, a quirky character who adds some comedic moments to the film.

Thomas Lennon plays Doug, one of Peter’s friends who offers advice during his journey.

Sarah Burns appears as Hailey, a character who interacts with Peter and adds to the story's humor.

Lou Ferrigno plays himself in a cameo role, providing a humorous twist in the narrative.