Doyle was born in Ireland to a human mother and a Brachen demon father. Doyle never knew his father or anyone on that side of his family, and his own demonic genes didn't physically manifest themselves until he was 21 years old. At that time, Doyle was a third grade teacher and a soup kitchen volunteer married to a lovely woman named Harriet, the love of his life. He didn't take the news of his demonic heritage very well, in spite of Harriet's acceptance of his other side, and his marriage ultimately disintegrated. Doyle hid behind the flimsy veneer of a ne'er-do-well hustler and con artist, seemingly more interested in where his next drink was coming from than helping others.
Later, he was approached by a fellow Brachen demon, Lucas, who told Doyle that The Scourge, a militant group of pure blood demons, was after all half-breeds and begged for Doyle's help. Doyle turned Lucas away, believing that this wasn't his problem. Soon after he received a vision, which he described as "splittin' migraines that come with pictures," in the throes of which he thought he was having a stroke. The vision showed him a group of massacred Brachen demons. Doyle searched the city to find out if what he had seen was real--it was. These visions, which come from The Powers That Be, are what led Doyle to Angel. As Doyle says, "We all got something to atone for," and therefore the two join forces to fight evil in Los Angeles. Once Cordelia Chase joins the team, Angel Investigations is officially formed.
A recurring gag throughout the episodes Doyle is featured in is that he will say something, and then say or do something that is the opposite of what he just said (in "City of" he tells Angel that it is right to help those in need, and then rudely tells an old lady who asks him for some money to "get a job"; in "Lonely Hearts", he tells two bar patrons that violence never solves anything, and then punches one of them out, starting a bar brawl that is soon broken up by Angel).
Doyle soon falls in love with Cordelia, but is afraid she will reject him upon finding out about his demonic heritage. He also forms a close, brotherly bond with Angel. Despite Doyle's reluctance to discuss his past, Angel and Cordelia learn about him when Harriet returns to his life, wanting a divorce so she can marry an Ano-Movic demon named Richard (the marriage is called off due to a ritual blessing of the clan that would require Richard to kill Doyle by eating his brain).
"Too bad we'll never know... If this is a face you could learn to love." -Doyle's final words
Doyle's past again comes back to haunt him when the Scourge returns, threatening the Listers, another tribe of human/demon hybrids. During the battle, Doyle sacrifices his own life to save his friends, the Listers, and the city of Los Angeles, from the Beacon, a device which could destroy any being "tainted" with human DNA structures. In doing so, Doyle fulfills the Listers' prophecy of the "Promised One", the bringer purported to save them from the Scourge in the last days of the 20th century. Before Doyle dies, he shares a passionate kiss with Cordelia (who had only recently learned of -- and accepted -- Doyle's demonic heritage) and laments that they would never know if whether or not she could come to fully love his demon side; this is his way of not only saying goodbye to Cordelia, but also passing his visions on to her.
After Doyle's death, he briefly appears in the third season episode "Birthday" and the fifth season episode "You're Welcome" -- both times courtesy of the Angel Investigations commercial he and Cordelia had made before he died.
In the fifth season of Angel, Lindsey McDonald assumes Doyle's identity in a failed attempt to convince Angel, Spike, and others that Spike, not Angel, is the subject of the Shanshu Prophecy. Both Angel and Cordelia were disgusted by this abuse of Doyle's legacy and name.
Powers and abilitiesEdit
"I get... visions. Which is to say great splitting migraines that come with pictures. A name... a face." -Doyle
Doyle receives prophetic visions from The Powers That Be, which includes images of people in peril, names, places in which evil is present or threats the Powers want to be dealt with. These visions also cause Doyle a great pain, though his half-demon physiology prevents his brain from suffering real damage.
His half-Brachen demon physiology grants him the ability to shift from normal human to demonic appearance (red eyes and green skin adorned with blue spikes), in which he has heightened sense of smell and superior strength, speed, stamina, and dexterity, the last of which allows him to twist his head around in such a manner as to fake a broken neck, something that allowed himself and Angel to enact a plan against the Scourge.
- Originally, it was Whistler (an ambiguous demon seen in Buffy's second season episode, "Becoming") who was to be a supporting character in the spin-off series starring Angel. Due to Max Perlich being unavailable, the character of Doyle was quickly created with similar character traits.
- At the TCA Writer's Guild of America West party in 2000, supervising producer David Fury stated, "Joss has bandied about, 'I love the idea of putting a character in the main credits as one of the stars of the show and then kill him right off the bat.' But in the case of Doyle, he didn't want to kill off Doyle. It just became a situation. The work situation became difficult... It's hard enough to make a television show without the headaches".
- Doyle was a series regular for part of the first season of Angel. He appeared in nine episodes overall.
- Because Christian Kane and David Boreanaz were both friends with Glenn Quinn, the pair were uncomfortable with the season five arc in which Lindsey McDonald pretends to be Doyle.
- In interviews before Quinn's death, creator Joss Whedon discussed plans for Doyle to return to the show as one of the season's big bad roles. Quinn died before anything could come of the talks.