Part of Home Alone featuring Macaulay Culkin, Joe Pesci, Daniel Stern, Catherine O'Hara, and John Heard.
He collected three Obie Awards for off-Broadway work before his film roles started gaining traction. The part that fixed him in Hollywood's mind came in 1974: Ezra Cobb, a grave-robbing serial killer based on Ed Gein in Deranged. The performance was quiet and specific in a way that made it worse than any scenery-chewing could. He was around fifty years old. The role confirmed what casting directors had started to figure out: he was the character actor you hire when a scene needs someone genuinely wrong.
Most people know Roberts Blossom as Old Man Marley, the supposedly murderous neighbor in Home Alone who turns out to be lonely and kind. It's a small part, but it followed him everywhere. The irony is that by 1990 he'd already played actual murderers and appeared in films by Steven Spielberg, Martin Scorsese, and alongside Clint Eastwood. Hollywood had been borrowing his face for decades, mostly for men who scared you. Home Alone was the first time they asked him to break your heart instead.
His daughter described him as 'a poet who made a living as an actor,' and the publishing record backs her up. He put out eight collections of poetry between 1962 and 2001 and reportedly kept a daily writing practice going for decades. A 2000 documentary, Full Blossom, featured Ed Asner and director Peter Brook reflecting on both sides of his work. He retired to Berkeley. Acting paid the bills. The poems were his real life.
Variety ran an obituary within days of his death on July 8, 2011. The Washington Post followed with a full obituary on July 14, framing his career largely around his role as Old Man Marley. He was survived by a daughter and a son.