Fell died Monday at the Motion Picture and Television Fund's retirement home in Woodland Hills, said Stan Schneider, his business manager.
Fell appeared in 35 movies, including The Graduate and Catch-22 and TV series including Burt Reynolds' 1970-75 detective drama Dan August.
But with his exasperated expression and droopy eyes, Fell was most easily identified for his supporting part as Stanley Roper, like it or not, Schneider said.
"I think he felt toward the end ... it typecast him. But it was the one everyone knew him as. Everyone called him Mr. Roper, on the street, wherever he went," Schneider said.
Fell and Audra Lindley played Stanley and Helen Roper on ABC's Three's Company, which debuted in 1977 and starred John Ritter, Joyce DeWitt and Suzanne Somers as their tenants.
The Ropers spent a fair amount of time poking into the unusual living arrangements of their young neighbors and the rest sparring between themselves. Fell and Lindley left the sitcom in 1979 to star in The Ropers, a spinoff that aired until 1980.
Lindley, 79, died in 1997 of complications from leukemia.
Three's Company continued until 1984 with Don Knotts as the new landlord and other cast changes.
A native of Philadelphia, Fell served as a tail gunner in the Pacific during World War II and earned his bachelor's degree in drama from Temple University.
He studied acting after his return from the war and struggled to win small parts in New York stage and TV productions, including 1954's Twelve Angry Men. His first regular series role was in the short-lived 1956 comedy Joe & Mabel.
After moving to Los Angeles in 1958, Fell won supporting roles in films and, in 1961-62, the part of police Detective Meyer in the drama 87th Precinct, based on the Ed McBain mystery novels.
His wit also won Fell repeated appearances as a guest of Johnny Carson on The Tonight Show.
Fell, who was divorced, is survived by two daughters.
Written by Lynn Elber