Wesley was once a watcher, and he took care of Faith, and then also Buffy, both vampire slayers. However, after great trouble with Buffy turning Rogue, Faith turning evil, and several other messups, Wesley loses his job at the watcher's council. He then becomes a rogue demon hunter. Honestly though, Wesley alone is hardly equipped for that kind of job, and is probably lucky he bumped into Angel when he did. He starts to team up with Angel, and soon becomes a regular employee. He instantly finds his place in the group, researching demons in his books and translating important scrolls.

Although Wesley is fired, along with Gunn and Cordelia, he returns stronger than ever. The gun shot wound he took, as well as becoming leader, made him much tougher and ready to take on evil. When Angel comes back, Wesley remains leader, and takes the group to their current status.

However, he makes a massive misjudgement after only a year in charge, he believes a prophecy which turned out to be completely faked. Sahjhan used his time travelling abilites to manipulate Welsey using the scrolls, and made him believe Angel would kill Connor. Wesley steals the child away, only to get it taken from him by Justine and Holtz.