Roberts Blossom, a durable character actor who was known for playing cantankerous old coots, both comic and sinister, but who may be best remembered as the kindly next-door neighbor in the comedy “Home Alone,” died Friday in Santa Monica, Calif. He was 87.

His death was confirmed by his daughter, Deborah.

Blossom amassed a long string of theater credits before hitting his stride as a character actor in the movies in the 1970s. He performed in dozens of films, usually in small but memorable roles.

He was an ill-fated patient in the George C. Scott film “The Hospital,” the delirious Wild Bob Cody in “Slaughterhouse-Five,” Paul Le Mat’s ornery father in “Citizens Band,” the farmer who once saw Bigfoot in “Close Encounters of the Third Kind,” the convict who paints the warden’s portrait in “Escape From Alcatraz” and the irate judge who sentences Michael J. Fox to community service in the local hospital in “Doc Hollywood.”

In a rare starring role, he was Ezra Cobb, a crazed farmer who unleashes mayhem, in the cult horror film “Deranged.” Posters for the film bore the tag line: “Pretty Sally Mae died a very unnatural death … but the worst hasn’t happened to her yet!”

He played against type in the hugely popular Christmas film “Home Alone.” As Old Man Marley, he was a threatening-looking geezer rumored to have killed his entire family, but the scary Marley turns out to be a sweet old fellow who befriends the character played by Macaulay Culkin.

Vincent Canby, in an article in The New York Times on outstanding small roles, praised Blossom in “Escape From Alcatraz” for “one of his quietest, creepiest performances to date” as Doc Dalton, an elderly inmate who incurs the wrath of the sadistic warden when he paints his portrait.

After being denied painting privileges, Doc cuts off his fingers in the prison woodworking shop, an expression of defiance and despair that Canby described as “serenely lunatic and unexpectedly moving.”

Roberts Scott Blossom was born on March 25, 1924, in New Haven, Conn., and grew up in Cleveland. After graduating from the Asheville School in North Carolina in 1941, he enrolled at Harvard but entered the Army after a year. On returning from duty in Europe during World War II he trained as a therapist, but he soon began acting in productions at Karamu House in Cleveland and then moved to New York.

He made his off-Broadway debut in 1955 in the Shaw play “Village Wooing,” for which he received the first of three Obie Awards. The others were for “Do Not Pass Go” (1965) and the Tankred Dorstplay “The Ice Age” (1976).

His Broadway credits included Edward Albee’s adaptation of Carson McCullers’ “Ballad of the Sad Cafe” and Sam Shepard’s “Operation Sidewinder.”

In 1988 he was cast in Peter Brook’s production of “The Cherry Orchard” at the Brooklyn Academy of Music. “As Firs, the octogenarian family retainer, Roberts Blossom is a tall, impish, bearded figure in formal black, stooping over his cane — a spindly, timeless ghost from the past, as rooted to the soil as the trees we never see,” Frank Rich wrote in a review for The New York Times.

On television Blossom appeared in the series “Naked City” in the 1950s and later in “Northern Exposure,” “Moonlighting,” “The Equalizer” and “Amazing Stories.”