His film credits included Sidney Lumet's "12 Angry Men" and Blake Edwards' "Days of Wine and Roses" and an early television highlight was appearing with Humphrey Bogart and Henry Fonda in a production of "The Petrified Forest." His performance in the classic 1959 musical "Gypsy" brought him a Tony nomination for best featured (supporting) actor in a musical.
He also appeared in several episodes of "The Twilight Zone," including a memorable 1963 one in which he played a negligent father whose son is seriously wounded in Vietnam. His other TV shows included "The Defenders" and the soap opera "The Greatest Gift."
Throat cancer took away his raspy voice for several years in the 1980s. When he was back on the stage for a 1993 revival of "Three Men on a Horse," the AP's review said, "His voice may be a little scratchy but his timing is as impeccable as ever."
"The only really stupid thing I ever did in my life was to start smoking," he said in 1996. Seeing people smoking in television and films "disgusts me, it makes me so angry — kids are watching," he said.
In his later years, he guest-starred on TV series including "Third Watch" and "Crossing Jordan" and appeared in a 2010 theatrical film, "Camera Obscura."
Klugman's hobby was horse racing and he eventually took up raising them, too.
"I always loved to gamble," he said. "I never got close to a horse. Fate dealt me a terrible blow when it gave me a good horse the first time out. I thought how easy this is.
"Now I love being around them."
A horse Klugman co-owned, Jacklin Klugman, finished third in 1980's Kentucy Derby and fourth in that year's Preakness Stakes.
Klugman's wife, actress-comedian Brett Somers, played his ex-wife, Blanche, in the "Odd Couple" series. The couple, who married in 1953 and had two sons, Adam and David, had been estranged for years by the time of her death in 2007.
In February 2008, at age 85, Klugman married longtime girlfriend Peggy Crosby, who was by his side when he died Monday.
His attorney Larry Larson wrote in an email that Klugman is also survived by two grandchildren and that memorial services have not been set.
Biographical material in this story was written by former AP staffer Polly Anderson, and AP sports writer Beth Harris contributed to this report.