The country singer got down on one knee in front of partner Lacey Buchanan while watched by fans, friends and family at the Citrus Bowl at Vero Beach High, reports People.
During a performance of his song 'Don't Think I Can't Love You', he brought Buchanan on stage for what seemed to be a dance, before popping the question.
Referring to the song's lyrics, he told her: "You're probably wondering where your ring is, right? I just said I can't buy you a big diamond ring or a big old house on the hill, but I promise you I'll love you forever and ever and ever."
An audience member revealed: "He was talking about how he'd thrown his hat up on the 50-yard line [during graduation] and now he was here in front of friends and family, and it seemed like the most appropriate [venue].
"He seemed to spontaneously decide to bring her out on stage and propose to her."
Lacey Buchanan has appeared in the star's videos for 'Barefoot Blue Jean Night' and 'Eight Second Ride'.
Watch the video for Jake Owen's 'Eight Second Ride' below: