Skateboarding legend Tony Hawk says he knew he'd made it when he played himself on 'The Simpsons'

In 1999, Tony Hawk became the first skateboarder ever to successfully complete a 900, a 900-degree aerial spin.

It happened at the sixth X Games in San Francisco, and it took Hawk 11 tries to land the move. "This is the best day of my life," he told the crowd.

But in hindsight, Hawk, now 48, doesn't see that moment as the pinnacle of his career. That came in 2003 - when Hawk played himself on an episode of "The Simpsons."

In the episode, "Barting Over," Bart meets Hawk and joins his skateboarding tour; then Bart's father, Homer, challenges Hawk to a skateboard match.

"To this day, I still get quoted on the streets from it," Hawk told Business Insider during an interview at the Success Makers Summit in April, hosted by American Express OPEN.

Even more importantly, guest-starring on "The Simpsons" showed Hawk that his personal passion - skateboarding - was gaining traction among a wider audience.

"It was a tipping point of skateboarding being accepted into the mainstream in a lot of ways. Even though Bart has always been a skateboarder per se, it was always considered more of a novelty or an outcast activity."

"It's still one of the highlights," Hawk said of his guest appearance. "I can't believe I got to do it."