While Underwood is now selling out arenas around the world, she was once just one of millions of hopefuls auditioning for the singing competition, eventually claiming America's votes thanks to her powerful vocals, lovable personality and a serious endorsement from Simon Cowell.
Read on to see how the singer went from Oklahoma girl to country superstar.
Underwood attended her initial audition in St. Louis, Missouri, with her mom, Carole, driving her to the casting. A college senior at the time, Underwood blew judges Simon Cowell and Randy Jackson away with her rendition of Bonnie Raitt's "I Can't Make You Love Me" and instantly earned a golden ticket to Hollywood.
Even though Underwood forgot part of the lyrics to Candi Staton's "Young Hearts Run Free" during Hollywood week, she advanced to the next round, which she would continue to do throughout the competition.
During the video package for the week, host Ryan Seacrest introduced Underwood to viewers as "farm girl Carrie Underwood" who's "more used to feeding the cattle with her father than singing on stage."
Through the competition, Underwood displayed her vocal range by performing songs including "Could've Been" by Tiffany, Jo Dee Messina's "Because You Love Me," Pat Benatar's "Love Is a Battlefield," Elvis Presley's "Trouble" and "Hello, Young Lovers" from the musical The King and I.
During the live shows, Underwood took a departure from her country roots and belted out Heart's "Alone," showing off her adaptable vocal skills while rocking some truly spectacular teased hair.
After her performance, Cowell predicted that Underwood would not only win the competition, but that she would go on to sell more records than any previous Idol winner — a prediction that has since come true. Aside from Underwood, only Season 1 Idol Kelly Clarkson has achieved such a level of success in the years after winning the show.
For her finale performance, the Oklahoma native took the stage to sing Martina McBride's "Independence Day," Guy Sebastian's "Angels Brought Me Here" and her winner's single, "Inside Your Heaven."
Underwood won the title of Idol with 37 million votes cast during the finale, racking up 500 million votes throughout the season. She released her debut album, Some Hearts, in November 2005, and the rest was history.
Photo Credit: Getty / Kevin Winter