Roberts Blossom was in New Haven, Connecticut to John Blossom, an athletic director at Yale University. He was raised in Cleveland but later moved to Shaker Heights, Ohio.
He attended Hawken School and graduated from Asheville School in 1941 and attended Harvard University for a year until he joined the Army and served in World War II in Europe.
He trained as a therapist and later decided to be an actor, and began directing and acting in productions at Karamu House and the Candlelight Theater in Cleveland and later moved to New York, where he supported himself by bundling feathers for hats and he practiced a disputed therapy called Dianetics. He also waited tables until he became a full-time actor.
He made his film debut in the bizarre and little seen independent feature "The Sin of Jesus" (1961). It wasn't until he was in his late forties and early fifties that Blossom really hit his stride acting in motion pictures.
Roberts gave a truly remarkable and unforgettable performance as demented middle-aged backwoods lunatic Ezra Cobb in the creepy horror cult favorite "Deranged" (1974).
Other memorable film roles include an ill-fated elderly patient in "The Hospital" (1971), a sickly soldier in "Slaughterhouse Five" (1972), Paul Le Mat's ornery father in "Citizen's Band" (1977), a farmer who saw Bigfoot once in "Close Encounters of the Third Kind" (1977), a venerable old felon in "Escape from Alcatraz" (1979), a kindly next door neighbor in "Home Alone" (1990), and a grumpy small town judge in "Doc Hollywood" (1991).
Blossom did guest spots on such TV shows as "Northern Exposure," "The Twilight Zone," "The Equalizer," "Moonlighting," "Amazing Stories," and "Naked City."
Moreover, Blossom was also a poet (he released some of his dramatic poems on video) and a playwright who won four Obies and a Show Business Award. After retiring from acting, Roberts settled in Berkeley, California and wrote poetry.
He died at age 87 in Santa Monica, California on July 8, 2011.

Source: Wikipedia.org