Prior to the Great War, Jazz was a DJ living in the Cybertronian city - the future city for the Autobots - Iacon. When the Decepticons began the infamous world war, Jazz chose to join the Autobots. Jazz's nature of responding well to change & improvisation, this eventually landed him the rank of 1st lieutenant. After the energon of Cybertron was sucked dry, Jazz accompanied Optimus Prime to find more in the universe & a new home (the other bots being Ironhide, Prowl, Wheeljack, Ratchet, and Bumblebee).