Williams had even called director Chris Columbus seeking the role of Hagrid but he was rejected.
The Harry Potter franchise has become a phenomenon that has given us many iconic and memorable characters. Based on the books by JK Rowling, there were a total of eight films that lasted for a decade. There are now spin-off prequels to Harry Potter that still continue to garner attention and do well in the box office. The film stars Daniel Radcliffe, Rupert Grint, and Emma Watson as the three leading characters: Harry Potter, Ron Weasley, and Hermione Granger. Many other iconic actors have also been a part of the franchise including Dame Maggie Smith as Minerva McGonagall, Alan Rickman as Severus Snape, Robbie Coltrane as Rubeus Hagrid, Tom Felton as Draco Malfoy, among others.
But a less known fact about the films is that there was a chance that Robin Williams could have been a part of the series as well. He was actually hoping to play Hagrid, the gentle half-giant who works as the gamekeeper at Hogwarts. The Dead Poet's Society actor was rumored to have coveted the role of Hagrid and had even approached the director of the first two Potter films, Chris Columbus, seeking the role. The part was denied to him on account of him being an American since at the time they had an "all-British and Irish cast" policy. The part ultimately went to Scottish actor Robbie Coltrane.
"There were a couple of parts I would have wanted to play, but there was a ban on American actors," Williams had said at the time. But he also remained optimistic that he could be a part of the film sequels in the future and had said in a very Robin Williams style, with a shrug, "Maybe one day. Say if [Harry] goes to Yale and becomes president."
This "Brits only" rule was also how Liam Aiken, also an American, and had previously worked with Columbus on Stepmom could not land the role of Harry. Janet Hirshenson the casting director said, “Robin [Williams] had called [director Chris Columbus] because he really wanted to be in the movie, but it was a British-only edict, and once he said no to Robin, he wasn’t going to say yes to anybody else, that’s for sure. It couldn’t be.”
This revelation comes to us from Reddit, posted on the Today I Learned subreddit. Fans who have grown up watching Williams and the Harry Potter series could not fathom anyone else being Hagrid other than Coltrane. Besides, Rowling's choice for Hagrid had already been fixated on Coltrane and she insisted that he should be the one to play the role. When Columbus asked her if she had any actors in mind for any of the characters, Rowling had said “RobbieColtraneforHagrid” all in one quick breath. The producers had then called Coltrane and said, “You’re playing Hagrid, and we’re having no arguments about it.”