They performed the group's No. 1 tune, "Pontoon," together on the show.
"He makes country music proud," said Little Big Town's Kimberly Schlapman.
Stevens was mentored by music exec L.A. Reid on the second season of "The X Factor," and won the Fox singing competition.
The 37-year-old country singer from Belton, Mo., beat runner-up Carly Rose Sonenclar, a 13-year-old schoolgirl from Westchester, N.Y., and teenage girl group Fifth Harmony on the finale that aired live Thursday night.