In 2009, Carrie performed a voice-over on Sesame Street as "Carrie Underworm", a worm celebrity who sings a song about worm pride before the Squirmadega Car Race.

Carrie was diagnosed with attention deficit hyperactivity disorder at age five and was prescribed Ritalin and Dexedrine, medicines she still takes as an adult.

"My momma would be so ashamed
It started off "hey cutie, where you from?"
And then it turned into "oh no! what have I done?"
And I don't even know his last name"

Carrie told Esquire magazine that her hit song, "Cowboy Casanova," was definitely NOT about Dallas Cowboys quarterback Tony Romo. "No. I would never immortalize a guy that did me wrong. I would never give him that much credit."

In 2011, an Ottawa radio station, 105.3 CISS-FM, stated that it would ban Underwood's music because her husband, NHL centre Mike Fisher, had just been traded from the Ottawa Senators to the Nashville Predators. Underwood's fans' went ballistic, and the station apologized, saying that its statement was meant as a joke, as it did not play Underwood's country songs anyway, and it was just a tongue-in-cheek way of wishing Fisher the best of luck in Nashville.

"Two Black Cadillacs" tells the story of two women who realize they are both involved with the same man and decide to kill him. Carrie says it was Stephen King's novel, Christine, that inspired the idea of having the car do the killing.

Carrie was a member of the Sigma Sigma Sigma sorority and is still close with her sisters.