Leonard King “Len” Lesser (born December 3, 1922, in New York City; died February 16, 2011, in Burbank, CA) was an American actor, best known for his role in Clint Eastwood's film, Kelly’s Heroes, and as Uncle Leo on Seinfeld. He first appeared as Uncle Leo in Season Two’s “The Pony Remark”. Len lost his life as a result of pneumonia which resulted from cancer. He was 88 years old.