Wesley was a British former watcher and, later, member of Angel Investigations. Wesley was killed trying to kill a powerful demon, and is now a reluctant spiritual employee of Wolfram & Hart.
Television Backstory
Buffy The Vampire Slayer
When Buffy the vampire slayer's Watcher, Rupert Giles, was fired by the Watcher's council in the third season of Buffy, Wesley was introduced as the new Watcher for Buffy and Faith. Immediately, Wesley's pompous attitude and lack of real experience turned off both Faith and Buffy. Ultimately, Wesley's attitude turned the two slayers against him, and they got out on a wild party night. In the end, Faith accidentally kills a man whom she mistakes for a vampire. This sends Faith on a downward spiral into a dark, evil place. Buffy eventually leaves the Watcher's council later in the season, effectively leaving Wesley useless. Despite this, Wesley offers assistance to her in the final battle against the evil Mayor.Angel
Wesley is next seen in LA partway through Angel the series' first season. Wesley is now a self-proclaimed rogue demon hunter, though it is later revealed that he was fired by the Watcher's council for his failure to control the two slayers and that the Council refused to pay for his ticket back England. Wesley is able to get reacquainted with Angel and Cordelia and eventually becomes a member of their private detective agency, Angel Investigations. Overtime, Wesley grows out of his pompous attitude.
In the second season of Angel, Angel fired the whole team after they questioned his methods. Wesley, Gunn, and Cordelia continued to operate Angel Investigations with Wesley as the leader. During this time, Welsey is shot and is forced to stay in a wheelchair for a portion of the season. When Angel realized he had treated them poorly and returned to his team, he offered to be their employee. Therefore, Wesley continued to be in charge.
During the third season of Angel, Wesley went through a difficult time. First, the woman Wesley loved, Fred, begins to date his friend Gunn. Then, Wesley discovered a prophecy in which Angel was destined to kill his son Connor. Wesley kidnapped baby Connor hoping to save him. Another group hoping to take Angel's baby attacked Wesley as he fled with the baby, taking the baby and slitting Wesley's throat. While in the hospital a distraught Angel attempted to kill Wesley by suffocating him with a pillow (all of this effictively ended his tenure as leader of Angel Investigations). Estranged from his friends, Wesley begins a relationship with Lilah Morgan, an attourney from the evil Wolfram and Heart law firm.
In the opening of the fourth season of Angel, Wesley works to locate Angel after he had been locked in a box and dropped to the bottom of the ocean. After finding him, he returned him to Fred and Gunn but took his leave. He opened up his own supernatural detective agency with his own employees. But eventually his paths return him to Angel Investigations and he returns to helping them when LA is under attack by The Beast and Jasmine. Lilah is killed which causes Wesley much sorrow, particularly since he will never know if their relationship was anything more than something purely physical. Lilah returns at the end of the season to offer Angel Investigations the oppertunity to run the LA branch of Wolfram and Heart.
Angel season five brought more heartache to Wesley. Wesley and Fred finally begin a romantic relationship, only to have Fred ripped away from them shortly afterwords. Fred is possessed by an ancient entity known as Illyria. By possesing Fred's body, Fred is essentially killed. Slowly, Wesley begins to try and help Illyria, because she is confused about being returned to the modern world. During Angel's attack on the Circle of the Black Thorn, Wesley was mortally wounded. Illyria came to him and held him during his final moments, because she was worried about him. She changes her appearance to that of Fred, to comfort him in his final moments. Then, Wesley died.
In canonical comics
In 2007, IDW Publishing began to publish a Joss Whedon-sanctioned comic continuation of Angel the series.
First Night
Wesley's First Night story was contained in Angel: After the Fall issue #7. Wesley had died, and thought he was in heaven with Fred. But he saw through the deception and realized it was all a Wolfram and Heart lie. They sent him back to LA (which was now in hell) to be their liason to Angel. They also sent him back as a ghost.
After the Fall
In Angel: After the Fall, Wesley is the last employee of the Wolfram and Heart LA branch. Wesley attempts to help Angel best he can, helping Angel locate ways to heal himself quickly (because Angel had now been made human by Wolfram and Heart) but he was unable to help him directly assist him because he was no longer corporeal. When Wesley meets Illyria, she reverts back into Fred (though she later changes back. It is revealed her that she has been switching back and forth ever since LA went to hell). Welsey then shows Illyria where his real body was. Illyria leaves the body in Spikes care when she goes with Angel on a mission. Spike remarks to Wesley that if Wolfram and Heart does anything to hurt whatever was left of Fred inside Illyria, Spike would find away to kill him. Wesley replies that, off-the-record, he was counting on it.
When the now vampire Gunn attacks Angel and removes all of the healing "mojo" keeping Angel alive, Wesley is transported to him (presumably by Wolfram and Heart). Wesley, frustrated that he can't do anything to aid the dieing Angel, cries towards the sky asking why Wolfram and Heart sent him back if he can't help. Wolfram and Heart reveal to him a vision to give to Angel. A vision of Angel killing thousands of people.
