Riley is the son of Llanview District Attorney Daniel Colson. He was named after Viki's first husband, the late Joe Riley, who worked with Daniel early in his career. Riley had problems with his father and became addicted to drugs. He managed to kick the habit by focusing on his love of music. Riley joined the band Midnight Logic, and began to develop feelings for its lead singer, Sarah "Flash" Roberts. Flash seemed unaware of Riley's feelings at first. She didn't find out how Riley felt about her, until she saw a song he wrote called "Flash of Light." She then returned his feelings. Riley has attempted to rebuild a relationship with his father. An incident where Daniel insulted Flash and then only apologized because she was Asa Buchanan's great-granddaughter had hindered this.

After a fight with Riley, Flash was attacked by the Music Box Killer. She survived the attack, but suffered throat damage and went to London for extensive therapy. Since the attack caused Flash to lose her voice, Riley took over as the lead singer of Midnight Logic. After Flash moved to London, Riley began to use drugs, but after forming a friendship with Jen Rappaport, he kicked the habit again. Eventually, he received a letter from Flash telling him she had found someone new, and he turned to Jen for comfort. They had a lot in common, including problems with their studies. Riley had even bought a paper off the Internet, but changed his mind at the last minute -- unfortunately, Jen had submitted it for him, and it took some serious explanations on her part to keep him from being expelled. Due to their low grades, they both ended up as part of the Love Crew. The two found themselves getting closer, but Riley didn't want to risk their friendship. After receiving another letter from Flash wanting to get back together, Riley realized that his heart now lay with Jen, and the two became an official couple.

Riley and Jen were moving forward in their relationship, so much so that he was even able to forgive her attempts to seduce Paul in order to get the sex tape of Lindsay and Rex away from him. Although they experienced a few bumps in their relationship, they soon moved in together. Unfortunately, as they were preparing for the next steps in their life together, Jen was also the main suspect in Paul Cramer's murder. Riley was in the uncomfortable position of being the son of the district attorney trying to solve the case, and the lover of the prime suspect. More than once Riley fought with his father over Daniel's conviction that Jen was the murderer. Riley and Jen finally separated, with Jen turning to Rex for help in clearing her own name. Riley tried desperately to convinced Jen that he loved her and even left her a voicemail telling her how much he believed in her, but she never got it. Jen was found dead in her car, an apparent suicide, and Riley was devastated.

Not knowing what to do with himself after Jen's death and his father in jail, Riley turned back to drugs and was eventually arrested for soliciting cocaine. Nora tried to make him do the right thing for himself and for Matthew and Riley entered rehab for his drug use.