Born on June 13, 1896, Larry Keating was a Hollywood veteran by the time he was cast as Roger "Sourpuss" Addison. The St. Paul, Minnesota native came to Mister Ed with credits in over 40 movies and having already worked with George Burns on The Burns and Allen Show. During World War II he joined Bob Hope in performing hundreds of military camp shows.

Keating, who made a living playing a next door neighbor, was quite pleased with his character on the show. In 1961 he said, "Neighbors, like any other human beings are of all types. Some are intelligent, some are silly. In most television series, they become stereotyped fools. I'm glad my role in Mister Ed is that of a very human person, somewhat wry in his observations, but withal bright and amusing."

The cast and crew of Mister Ed enjoyed working with Keating and the feeling was mutual, even when it came to Ed. "I love my neighbors - Alan Young, Connie Hines and that gay blade, Mister Ed, the horse with the wagging tongue, " he said. "They're all sweethearts. But best of all I love my wife in the series, Edna Skinner - and so does my real wife." The cast and crew were devastated to learn he was diagnosed with leukemia in early 1963. Despite his illness, Keating continued acting until a week before his death on August 26, 1963. Surviving Keating were his wife, two sons, stepson, brother, and two grandchildren. His final appearance on the show was the Season 4 premiere, Leo Durocher Meets Mister Ed.

• Larry Keating's IMDb page
• Pay your respects to Larry at Find A Grave