Casting is everything when making a great movie or television show. And this is especially true of the Harry Potter movies. After all, the books were global sensations, and an entire generation needed to have their imaginations fulfilled. On top of this, picking the right young stars for the first Harry Potter film, 'The Sorcerer's Stone' (originally, 'The Philosopher's Stone') was essential due to the fact that audiences would be following these young actors for many films to come.

While there was another actor set to play Harry before Daniel Radcliffe came on the scene, ultimately Sorceror's Stone director Chris Columbus, producer David Heyman, and author JK Rowling picked the right guy for the job. In fact, the creators of the movie picked a trio of young actors who have a massive following to this day. More importantly, Daniel Radcliffe, Rupert Grint, and Emma Watson brought this world to life.

Here's how they were cast...

Harry Ron and Hermione
PluggedIN

Finding The Right Actors Was A Massive Challenge... Especially When It Came To Harry

Thanks to a fantastically revealing oral history of the casting of Harry Potter by Closer Weekly, we now know what exactly went into finding Daniel Radcliffe, Rupert Grint, and, of course, Emma Watson. In the article, a number of the people behind the movies, as well as the actors, were interviewed about how the casting came to be.

"Finding the right actors to play the characters was a very big challenge," executive producer David Heyman explained to Closer Weekly. "It was not easy to find a boy who embodied the many qualities of Harry Potter. We wanted someone who could combine a sense of wonder and curiosity, the sense of having lived a life, having experienced pain; an old soul in a child’s body. He needed to be open and generous to those around him and have good judgment."

Truth be told, they knew they'd find the right boy for the job when they saw him... But it took eons for that to happen...

"We had auditioned hundreds of actors for the role of Harry, but with little luck," director Chris Columbus said. "Then, the first casting director, in a fit of total frustration, threw up her arms and said, 'I just don’t know what you want!' Sitting on a shelf in the office was a video copy of David Copperfield, starring Daniel Radcliffe. I picked up the video box, pointed to Dan’s face, and said, 'This is who I want! This is Harry Potter.'"

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But when the team approached Daniel Radcliffe, his parents were initially very reluctant. After all, the role was bound to change their son's life forever.

"We made it very clear that we would protect their son," Chris Columbus, who had a history of working with children, said. "We knew from the start that Dan was Harry Potter. He had the magic, the inner depth and darkness that is very rare in an 11-year-old. He also has a sense of wisdom and intelligence that I haven’t seen in many other kids his age. We knew we made the right choice after sending Jo [Rowling] a copy of his screen test. Her comment was to the effect, 'I feel as if I’ve been reunited with my long-lost son.'"

But What About Emma And Rupert?

Of course, finding the boy to play Harry Potter was the most important part, but finding the young performers to play his best-friends was almost as vital. This is because the success of the franchise really lay at the feet of the chemistry between these three. Sure, casting Alan Rickman as Snape, Dame Maggie Smith as McGonagall, or Richard Harris as Dumbledore was a key way of snagging the interest of older audiences, but nothing was as special as the bond between Harry, Ron, and Hermione.

Young cast of Harry Potter
Britanica

"When it came to Ron Weasley, we immediately fell in love with Rupert Grint," Chris Columbus said. "He’s extremely funny and has such an incredibly warm presence."

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Like Harry, the casting director, the director, and the producers searched for an up-and-coming star among hundreds of auditioning children.

"I decided to do my own audition video, pretending to be one of my drama teachers," Rupert Grint explained. "I dressed up like my teacher, who’s a girl, so it was kind of scary. Then I made up this rap song about how much I wanted to be in the film. I guess it worked, because I had a bunch of auditions. It was so cool when I was cast. It was the coolest moment in my life. I’d just been doing school plays and stuff. One time, I was a fish in Noah’s Ark, and then I was in Harry Potter — that’s a big step!"

Related: The Truth About How Emma Watson Was Cast In 'Harry Potter'

"Some people came round to my school in Oxfordshire and said, 'Do you have anyone who would like to audition?' So I had an audition at my school," Emma Watson said. "I think I ended up doing over five auditions. My dad told me, 'You do realize there are going to be, like, a thousand girls auditioning, right?' And I was kind of like, 'Oh, okay… I’ll, um, keep that in mind.' I tried to enjoy it instead of desperately trying for it. I found out that I had gotten the part when [producer] David Heyman invited Rupert Grint and me to come in. We sat down in his office — all very casual — and he said, 'You’ve got the part.' I was so shocked and I just stood there and said, 'Pinch me.'"

Next: 15 Photos Of The Harry Potter Cast Behind The Scenes