Buffy and Riley fought demons together and continued saving each other's lives and the world, although Riley was never quite let into Buffy's inner circle. The Initiative was destroyed at the end of the fourth season, and Riley was relieved of his military standing. He was left at loose ends, and his behavior became reckless. Seeking thrills, he began to let vampires feed from him, which Buffy discovered in the season five episode "Into the Woods". His behavior, as well as a sense that Buffy would never truly love him, led to their breakup. Riley left Sunnydale to join another army unit fighting demons elsewhere, and left the show.

Riley returned in the season six episode "As You Were", in which he showed up unexpectedly, tracking a demon about to hatch eggs that could wipe out Sunnydale. However, he did not return to make up with Buffy, having recently gotten married to a fellow demon hunter. The battle done, Riley left Sunnydale, never to return again. Riley was however mentioned in season 7 when Buffy asked for the Initiative to help Spike.

Riley, the opposite of both the eternally brooding Angel and the tortured "bad boy" Spike, held out the possibility of normalcy in Buffy's life. Riley is also notable in that he is the only boyfriend of Buffy who had a friendship with her usually jealous friend Xander.