Boyle died Tuesday evening at New York Presbyterian Hospital after a long battle with multiple myeloma and heart disease, his publicist, Jennifer Plante, told TheShowBuzz.com.
"I am deeply saddened by the passing of Peter Boyle," Ray Romano said, adding that Boyle was a mentor to him from the early days of "Everybody Loves Raymond."
"He gave me great advice, he always made me laugh, and the way he connected with everyone around him amazed me. The fact that he could play a convincing curmudgeon on the show, but in reality be such a compassionate and thoughtful person, is a true testament to his talent," Romano said.
"He could play this guy who seems scary but really underneath it has this heart you know? And get a laugh doing it," said Romano. "To get the audience to hate your character... but love you is unique."
"It's like losing a spouse," said Doris Roberts, who played Boyle's wife on the sitcom.
While a generation of TV viewers knows him as Frank Barone - with his trademark "Holy crap!" line - Boyle had a respectable career long before "Everybody Loves Raymond" debuted in 1996, including a part in Martin Scorsese's "Taxi Driver," in which he played a philosopher cabbie who counseled Robert DeNiro's angry character.
Boyle was also close friends with John Lennon, who was best man at Boyle's wedding.
A member of the Christian Brothers religious order who later turned to acting, Boyle first caught the public eye in the title role of the 1970 sleeper hit "Joe," playing an angry, murderous bigot at odds with the emerging hippie youth culture.
The latter film also led to the actor meeting his wife, Loraine Alterman, who visited the set as a reporter for Rolling Stone magazine. Boyle, still in his monster makeup, quickly asked her for a date.
The defining moment for Boyle in "Frankenstein" came when Gene Wilder, in the title role of the mad scientist, introduced his creation to an upscale audience. Boyle, decked out in tails, performed a song-and-dance routine to the Irving Berlin classic "Puttin' On the Ritz."
It showed another side of the Emmy-winning actor, one that would be best exploited in "Raymond" as the curmudgeonly Frank Barone.
"He's just obnoxious in a nice way, just for laughs," Boyle said of the character in a 2001 interview. "It's a very sweet experience having this (success) happen at a time when you basically go back over your life and see every mistake you ever made."