LONDON — Richard Griffiths was one of the great British stage actors of his generation, a heavy man with a light touch, whether in Shakespeare or Neil Simon. But for millions of movie fans, he will always be grumpy Uncle Vernon, the least magical of characters in the fantastical ‘‘Harry Potter’’ movies.
Mr. Griffiths died Thursday at University Hospital in Coventry, central England, from complications following heart surgery, said his agent, Simon Beresford. He was 65.
‘‘Harry Potter’’ star Daniel Radcliffe paid tribute to the actor Friday, saying that ‘‘any room he walked into was made twice as funny and twice as clever just by his presence. I am proud to say I knew him.”
Mr. Griffiths won a Tony Award for ‘‘The History Boys’’ and appeared in dozens of movies and television shows. But he will be most widely remembered as a pair of contrasting uncles — Harry Potter’s Uncle Vernon Dursley and Uncle Monty in the cult film ‘‘Withnail and I.’’
Mr. Griffiths was among a huge roster of British acting talent to appear in the ‘‘Harry Potter’’ series of films released between 2001 and 2011.
His role, as the grudging, magic-fearing guardian of orphaned wizard Harry, was small but pivotal.
Mr. Griffiths once said he liked playing Uncle Vernon ‘‘because that gives me a license to be horrible to kids.’’
But Radcliffe recalled the actor’s kindness to the young star.
‘‘Richard was by my side during two of the most important moments of my career,’’ said Radcliffe, who in 2007 starred with Mr. Griffiths in a London and Broadway production of ‘‘Equus.’’
‘‘In August 2000, before official production had even begun on ‘Potter,’ we filmed a shot outside the Dursleys’, which was my first ever shot as Harry. I was nervous, and he made me feel at ease.
‘‘Seven years later, we embarked on ‘Equus’ together. It was my first time doing a play, but, terrified as I was, his encouragement, tutelage, and humor made it a joy.’’
Earlier, Mr. Griffiths was the louche, lecherous Uncle Monty to Richard E. Grant’s character Withnail in ‘‘Withnail and I,’’ a low-budget British comedy about two out-of-work actors that has become a cult classic. Years after its 1987 release, Mr. Griffiths said people would regularly shout Monty’s most famous lines at him in the street.
‘‘My beloved ‘Uncle Monty’ Richard Griffiths died last night,’’ Grant tweeted Friday. ‘‘Chin-Chin my dear friend.’’
A huge stage presence with a grace rendered all the more striking by his physical bulk, Mr. Griffiths created roles including the charismatic teacher Hector at the emotional heart of Alan Bennett’s school drama ‘‘The History Boys.’’ He won an Olivier Award for the part in London and a Tony for the Broadway run, and repeated his performance in the 2006 film adaptation.
National Theatre artistic director Nicholas Hytner, who directed ‘‘The History Boys,’’ called his performance in that play ‘‘a masterpiece of wit, delicacy, mischief, and desolation, often simultaneously.’’