Little is known about Wesley's childhood, only that it was a largely unhappy one. In the episode "Lineage", it is revealed that, at the age of six or seven, Wesley attempted to resurrect a dead bird using a mystical scroll stolen from his father's library. As a teenager he attended an English all-boys preparatory school where he trained to become a Watcher; members of a secret organisation who battle evil and train Vampire Slayers. In order to improve his performance, Alexis Denisof came up with a background story for Wesley regarding his father. The writers used this story in the show, alluding to it in early Angel episodes such as "I've Got You Under My Skin", and "Belonging". In "I've Got You Under My Skin" viewers are led to believe that Wesley may have been psychologically abused as a child, and that his various insecurities may be in part a result of his father's unrealistic expectations of him. While discussing Wesley's character development over the course of Angel, Denisof explains "I decided that Wesley was internally confronting his father and that released him a little bit and made him less repressed",

Denisof had earlier stated that he thought "it's better for the father [of Wesley] to be kept in the background and not become part of the story. When Wesley's father finally did appear in Angel Season Five, he said, "I had mixed feelings [at first]. It was a lot of pressure to have to define something that had been speculated about for many years. I was worried that by making it specific, it would lose its power, both in the mind of the character and in the minds of the audience. All my concerns disappeared as soon as I read it. There are responses to powerful figures in your life, like your parents, that you can't necessarily control. Wesley's a very controlled person on the exterior and presents a very collected persona to the people around him, being with his father he would no longer be able to control his responses. That's one of the things I wanted to explore with this, the subtle ways in which you respond to the conditioning of your parents. Wesley has difficulty around his father on a physical level, on an emotional scale, and on an intellectual scale. He is extremely intimidated by his father, and at the same time, still seeking the approval that we all essentially want from our parents when we're children.

The [shooting of the cyborg Wesley believed to be his father] was an exhilarating moment in which there was the most dangerous person in his life on every level, and there is a woman he is obsessed with. And to have the woman jeopardized by something as dangerous as his father - I played that moment as a moment of pure instinct. Wesley is a centered in his intellect and is more uncertain in his emotional life, but in that moment, he becomes pure instinct because he has to choose between the woman he loves and his father."