Doyle, a half demon, half human, is the man who gets the ball rolling with Angel Investigations. In Los Angeles, 1999, he finds Angel and tells him of the visions he gets from the Powers That Be, and how Angel could use these to really make a difference in the city. After their first mission where they successfully save Cordelia, the two pair up to make Angel Investigations. Doyle is clearly a wise person with a great deal of historical knowledge. He is always first to recognise artefacts and other intersting things that Angel finds along the way. His astonishment at seeing the Ring of Omahrra is a clear indication of his knowledge. His life is twisted around a little by the arrival of his wife, asking for a divorce, but he manages to stay on track.

He instantly likes Cordelia, and although he is rejected many times over, his bravery begins to shine as the episodes pass, and soon things look as if he and Cordelia could get together, but they never get the chance. Doyle's vision of demons being pursued by the scourge leads him on his final mission.

In order to save the demons, Angel is willing to sacrifice himself, but Doyle knocks Angel out in order to do it himself. Doyle had once let down his fellow demons by ignoring the threat of the scourge, and now this was his chance for redemption. Though he never considered himself hero material, as he says, you never know until you're tested. He sacrifices himself to save his friends, and the many demon refugees.

Doyle's final gift was to Cordelia. He passes on his vision, his one special possession, in a final kiss to say goodbye.