The Texas-born waitress became a star overnight by winning over the Fox series' original trio of judges: Simon Cowell, Paula Abdul and Randy Jackson. She edged out runner-up Justin Guarini (of From Justin to Kelly infamy) and other worthy contestants thanks in part to what would become one of her signature tunes, "A Moment Like This."
"18 years ago today was the finale of the first season of American Idol and it changed my life! I'm still hustlin 18 years later because I know I am blessed to have the opportunities and I still love my purpose!," Clarkson Tweeted on the finale's anniversary. "Find your purpose! Seek out what keeps that fire in you burning."
Since that life-changing night in Hollywood, Clarkson has gone on to score Billboard pop hits, win Grammy awards and continue to appear on network television on The Voice, America's Got Talent and her own talk show for NBC, The Kelly Clarkson Show.
All of these years later, Ryan Seacrest is the only constant from American Idol's first season. The show now airs on ABC and features judges Katy Perry, Lionel Richie and Luke Bryan.
If Clarkson's not the American Idol winner with the furthest reach into popular culture, she's a close second to country superstar Carrie Underwood.
During an appearance on The Kelly Clarkson Show, Cowell sang Clarkson's praises.
"Apart from the fact that we had so much fun, and look, to credit you Kelly, we wouldn't be here without you," Cowell said (as quoted by People). "The fact that you're one of the most successful singers in the world.
"I have to say something about you, Kelly. Unlike the majority, you are the same person off-camera as you are on camera," he added. "You've always respected people and you've been very loyal and you're a great friend. I'm absolutely thrilled for you, genuinely. You've worked hard."