Sheldon Leonard Bershad was born on February 22, 1907, in Manhattan, New York City, to middle-class Jewish parents Anna Levit and Frank Bershad. He graduated from Syracuse University in 1929.
As an actor, Sheldon Leonard Bershad specialized in playing supporting characters, particularly gangsters or "heavies", in films such as It's a Wonderful Life, To Have and Have Not, Guys and Dolls, and Open Secret. He was known for his distinctive New York accent, often delivered from the side of his mouth.
Sheldon Leonard Bershad began his radio career in 1945, playing an eccentric racetrack tout on The Jack Benny Program and later in the TV series of the same name. He also appeared on The Damon Runyon Theatre radio show, The Adventures of the Saint, and The Adventures of Maisie.
In addition to his acting work, Sheldon Leonard Bershad provided the voice of lazy fat cat Dodsworth in two Warner Bros. Merrie Melodies cartoons directed by Robert McKimson. He also played against type in the significant role of Chief Ogane, a Native American warrior, in the adventure movie The Iroquois Trail.
Later in his career, Sheldon Leonard Bershad established a reputation as a producer of successful television series, including The Danny Thomas Show, The Andy Griffith Show, Gomer Pyle U.S.M.C., The Dick Van Dyke Show, and I Spy. He also directed several TV series episodes, including four of the first eight episodes of the TV series Lassie.
Sheldon Leonard Bershad provided the voice of Linus the Lionhearted in a series of Post Crispy Critters cereal TV commercials, which led to a Linus cartoon series that aired on Saturday and Sunday mornings on CBS and ABC. He also starred in his own television show, Big Eddie, where he played the owner of a large sports arena.