He began as a member of the Military Police, but became disgusted with the policies of the Paradigm Group and became a free agent. It was after this time that he met Norman Burg, who introduced him to the Big O; a megadeus which had been "waiting" for him to come. It was after that time that Smith became a negotiator. It was after he was hired to conduct negotiations between Beck Gold and Miguel Solderno that his life began to change, as he met R. Dorothy Wainwright, an android.
After her introduction into his life, Roger Smith continued to battle criminals and rogue megadeuses, but slowly it became apparent that there were deeper secrets in Paradigm City than had been previously suspected. Roger began to question his own past, including his inexplicable expertise with piloting the Big O and his mysterious, ingrained fear of the deep tunnels beneath Paradigm. He gained further suspicions from his encounters with Angel and Schwarzwald. He also became close to R. Dorothy, although their relationship often seemed antagonistic.
Finally, Smith became the target of RD, a mysterious android hunting down people who believed they had memories from before the Event that wiped out the memories of the others who lived in Paradigm. Smith, like the others who had been murdered, began to have brief but vivid visions of some great conflict involving the megadeuses. It was after the battle with R.D., which he barely survived, that he had a full flashback to the life of a different Roger Smith, in a very different (apparently pre-Event) Paradigm.
After returning to reality, Smith became embroiled in the machinations of Alex Rosewater and the Union, a foreign power. He also grew closer to Angel, but his uncertain relationship to R. Dorothy kept them from getting too close. Eventually he came into conflict with the Union as they tried to destroy Paradigm, and Rosewater as he used the power of Big Fau to dominate. During the final battle, after R. Dorothy's memory was stolen to complete Big Fau, Smith had brief visions of other Paradigm cities; he was saved from drowning by R. Dorothy, and defeated Rosewater afterwards. He was just in time to face Big Venus (under the control of Angel) as it wiped out Paradigm, and convinced her to create a new reality; with a new Roger Smith, but apparently no megadeuses.
In addition to the Big O, Roger Smith also had access to a specially armed and modified car and other equipment. He abided by a personal code of conduct, which included never using guns in personal combat and treating ladies in a gentlemanly manner.
It appeared that Roger Smith was a "recurring character" in the various Paradigm Cities, a common element of sorts. One incarnation was a homeless wanderer; another was a soldier in a war between megadeuses; yet another helped found Paradigm City. The exact nature of the various Rogers was never specified.