Born in Buffalo, New York, in 1920, Greenbaum studied at the Massachusetts Institute of Technology and the Sorbonne in Paris. He moved to New York City in the mid-1930s to try his luck as a writer, eventually finding employment in radio, writing continuity for a series starring the Canadian folk singer Oscar Brand.
When Brand's show was cancelled, work in the Big Apple suddenly began playing hard to get. "The next poverty-ridden radio personality I wrote for," said Greenbaum, "was myself." To do the show in question (Greenbaum's Gallery) he had to return to Buffalo. Many years later, giving advice to aspiring comedy writers, he advised: "If you have a hometown (where you can possibly live with your folks) and can't get a foothold in the Big City, it might be a good idea to find a station back home."
When he again left the security of Buffalo to challenge New York he discovered ethnic radio, "Big cities have stations catering to all nationalities", he said. "I worked my way into a Jewish station, not only writing, but also performing, for 15 dollars a week. It more than paid my rent."
After serving as a naval aviator and flight instructor in the Marshall Islands during the Second World War, Greenbaum returned to New York, this time seeking work as a television writer. With Jim Fritzell he collaborated on scripts for Mr Peepers (1952), a stylish sitcom starring Wally Cox as a timid small-town science teacher and giving Tony Randall his first important role. When the series was cancelled, NBC-TV received over 10,000 letters of protest. A month later Mr Peepers returned, running for three years and winning a Peabody Award.
In a 22-year partnership, Greenbaum and Fritzell also won three Writers' Guild awards and four Emmy nominations, and collaborated on more than 150 scripts. These included the Walter Brennan sitcom The Real McCoys (1957-62), The Andy Griffith Show (1960-68) and M*A*S*H, on which they worked for five years, contributing 35 episodes.
When McLean Stevenson, who played Colonel Henry Blake suddenly decided to leave M*A*S*H at the end of the third season, Greenbaum and Fritzell wrote the episode "Abyssinia, Henry" which not only effected Blake's departure from the series, but also movingly highlighted the wastefulness of war. In this famous episode, Blake received his army discharge and was returning to his wife and children in America when he died in a plane crash. No leading character in an American half-hour television series had ever died before, and the impact was enormous.
For the big screen, Greenbaum and Fritzell collaborated on the Jack Lemmon vehicle Good Neighbour Sam (1965), which satirised the cut-throat world of advertising. For Universal they wrote three films starring Don Knotts, who had co-starred in The Andy Griffith Show, The Ghost and Mr Chicken (1966), The Reluctant Astronaut (1979) and The Shakiest Gun in the West (1968). Their film Angel in My Pocket (1969) brought Andy Griffith back to the big screen. They also provided the original story for the Phyllis Diller comedy Did You Hear the One About the Travelling Saleslady? (1968). In 1979 the team had just finished writing a television pilot called, prophetically, Heaven on Earth when Fritzell suddenly died of a heart attack.
Independent of his partner, Greenbaum played cameo roles in Andy Griffith's murder-mystery series Matlock, wrote for The George Gobel Show, flew, made kinetic sculptures and wrote two books, including an autobiography.
Everett Greenbaum, writer: born Buffalo, New York 1920; married Deane Ward (one daughter); died Encino, California 11 July 1999.