The 32-year-old country singer won Favorite Country Female Artist, beating out fellow nominees Kelsea Ballerini and Miranda Lambert.
"Thank you, fans. I thank God for you, and for country music. And for all the blessings. I still don't know how I'm on this stage right now, to be honest. I'm so, so thankful. To my husband and my little Isaiah, you guys are the best things in my life. So much to be thankful for," Underwood said as she accepted her award.
Underwood, who won American Idol's fourth season, toldAccess Hollywood she could completely relax after receiving her award because she was "done" with everything. She joked about being able to change clothes and eat some french fries.
Underwood was extremely thankful to her fans, who voted for her to win Favorite Country Female Artist.
"Time and time again, they have proven to me -- not that they need to prove anything to me -- but they vote and they work. They are amazing," she said.
Underwood also insisted she'll try to make an appearance on American Idol's fifteenth edition next year. Idol host Ryan Seacrest already revealed he's trying to recruit all former show judges to come back for the Fox series' final season.
"We're trying to figure out my schedule at this point, because I will be on tour next year, so it's kind of a mess. But I'd love to, hopefully," Underwood admitted to Access Hollywood after last night's awards show.
"It changed television, it changed the music industry. Fifteen years is a long time for any show to be on TV and they've done so much for so many artists like myself who just wanted to be in the game and didn't know how to get there."
In addition to Underwood, several other artists with reality TV ties won awards.
Rihanna, who served as The Voice's ninth season universal mentor, walked away with Favorite Soul/R&B Female Artist. Twelfth-season Idol judge Nicki Minaj won Favorite Rap/Hip-Hop Artist and Favorite Rap/Hip-Hop Album for "The Pinkprint." One Direction, who finished Season 7 of The X Factor UK in third place, won Artist of the Year and Favorite Pop/Rock Duo or Group.