Which actor played Uncle Leo on 'Seinfeld'?

Len Lesser played Uncle Leo on Seinfeld.

Uncle Leo is Jerry Seinfeld's fictional uncle and the brother of Jerry's mother, Helen. Len Lesser portrayed the character throughout the series, giving him a distinctive personality built around complaints, unsolicited physical closeness, and his booming greeting: "Jerry! Hello!" The role became one of the show's most recognizable supporting performances.

Lesser first appeared as Uncle Leo in "The Pony Remark," the second-season episode that introduced the character. Uncle Leo eventually appeared in 15 episodes, including appearances across every later season and the two-part series finale. His last name is never revealed on the show, and his son Jeffrey is frequently mentioned.

Viewers sometimes confuse the actor with Jerry Stiller, who played George Costanza's father, Frank Costanza. Barney Martin played Morty Seinfeld, Jerry's father, while John Randolph played the character in the show's original pilot version. None of them played Uncle Leo. Len Lesser was also known for playing Garvin on Everybody Loves Raymond.