The star also did her own styling, hair and makeup, Fox News can confirm.
Swift, 30, took to the stage to perform her hit "Betty," which served as the premiere performance of the song, but also the singer's return to the ACM Awards stage for the first time in seven years.
For her appearance at the Grand Ole Opry House, the "Shake It Off" singer donned a long-sleeved sparkling red top with long beige pants and dark-colored heels with a gold chain around her ankles.
Her hair was done up in a simple up-do and showed off her short bangs.
People magazine reports that the outfit was made up of entirely Stella McCartney.
Swift has earned eight ACM Awards herself and 22 other nominations.
Swift previously opened up about the meaning of "Betty," which, like much of her music, tells a story about love.
"[James] has lost the love of his life basically and doesn't understand how to get it back. I think we all have these situations in our lives where we learn to really, really give a heartfelt apology for the first time," Swift said, per People.
The popstar added: "Everybody makes mistakes, everybody really messes up sometimes and this is a song that I wrote from the perspective of a 17-year-old boy. I've always loved that in music you can kinda slip into different identities and you can sing from other people's perspectives. So that's what I did on this one."