Walter Matthau ( October 1 , 1920 -- July 1 , 2000 ) was an American comedy actor , most famous for his role as Oscar Madison in The Odd Couple and his many collaborations with fellow Odd Couple star Jack Lemmon . Walter Matthau ( October 1 , 1920 -- July 1 , 2000 ) was an American actor best known for his role as Oscar Madison in The Odd Couple and his frequent collaborations with Odd Couple star Jack Lemmon , as well as his role as Coach Buttermaker in the 1976 comedy The Bad News Bears .