DecembeRadio all began playing music in their teens. Josh Reedy and Brian Bunn attended the same schools, and the former's rendition of "Johnny B. Goode" on guitar at a middle school talent show convinced Bunn to take up guitar, as well. "Our first year of high school, we started a Top 40 band. We played Hootie & the Blowfish covers and that sort of thing. Then shortly thereafter, we realized that God had given us these gifts, and we wanted to utilize them for him," recalled Bunn. The pair decided to pursue music full time upon graduation from Auburn High School in Riner, Virginia.

After a performance opening for evangelist Billy Wayne Arrington in Dublin, Virginia, Arrington invited Bunn and Reedy to join his touring band. Bunn credits Arrington with helping to alter the band's focus: "We were playing music for God, but we didn't really know why we were doing it. It was more so to be 'rock stars', per se, and just use God as a way to get there. And so he really helped us flip-flop that and get it the way it should be."

Eric Miker started playing guitar at the age of sixteen when his father taught him a few chords. After two years at West Virginia University, Miker felt a calling to go into Christian ministry. He met Bunn and Reedy at a youth event in West Virginia, where he impressed the pair with the "Sweet Child o' Mine" guitar lick that he added to a worship song. Shortly thereafter, Miker joined the band full time, playing with Arrington for a few months before the trio ventured out on their own. The band came up with its name after Miker photographed an old radio with a calendar on top of it open to the month of December.
DecembeRadio's music is strongly influenced by hard rock and blues-rock from the 1970s, be it directly through artists like Aerosmith and The Rolling Stones, or through later interpreters such as The Black Crowes and Lenny Kravitz. The band's label, Slanted Records, also notes the influence of Porcupine Tree, Audioslave and other contemporary rock bands. In addition, their music has been compared to U2, Stone Temple Pilots and King's X. "We feel like God has called us to a musical style that is not represented as much as, say, more modern, harder edged bands. We are bringing the old school to the new school," says Josh Reedy.

The band members credit family members with introducing them to rock music through old collections of vinyl records. Boone Daughdrill cites "When the Levee Breaks" as his biggest influence. "When I heard that drum fill come in the intro...oh! I was a little kid and my uncle had all of the Zeppelin records. He was a drummer too and he would always be like, 'Man, check these guys out.' I was only three or four and I didn’t know what music was, but I knew that I loved that."