LOS ANGELES, California (X17online) - Seinfeld actor Len Lesser died in his sleep Wednesday morning in Burbank, California, of complications from pneumonia. He was 88.

Best known as Jerry Seinfeld's Uncle Leo on TV's Seinfeld, Lesser actually made more than 500 film, television and stage appearances.

He has appeared on ER, Mad About You, Thirtysomething, The Bob Newhart Show, The Mod Squad, and many others.

Lesser is survived by a son, David, and a daughter Michele, and grandchildren, Jonathan, Kayla, and Mayah.

His daughter, Michele Lesser, told CNN: "It was very peaceful. He was a great grandpa, and an amazing father. He had a heart of gold and a sense of humor of platinum."

Sony Pictures Television