Like his father the Sheriff, Kyle is a foil and an an antagonistic character in season 1–first as the boyfriend who tries to keep his relationship with Liz strong in spite of her obviously growing connection to Max. After Liz breaks up with him, Kyle becomes slowly more obsessed with finding out Max’s secrets, although the two of them bond hilariously while drunk in the episode “Blind Date.” At the end of season 1, Kyle is so distrustful of Max that he sneaks into the UFO center with one of his father’s pistols, inadvertently provoking the end of our heroes’ confrontation with Agent Pierce.
In season two, Kyle struggles with the deeper meaning of all the secrets he’s learned, and the many ways knowing them changes his life, especially Tess Harding coming to live in his house. After some initial resentment, he quickly grows fond of Tess, even calling her “my favorite Martian”, and asks her to the Junior Prom in “Heart of Mine”, before finally blurting out that he thinks of her as a sister, not a romantic partner. Kyle also becomes increasingly obsessed with the idea that like Liz, he will develop alien characteristics beyond his control.
In season three, Kyle’s friendship with Isabel grows deeper, and he becomes her confidant as she navigates her relationship with Jesse Ramirez, which estranges her somewhat from Max and Michael. At the end of season three, he goes with the aliens as they leave Roswell behind, pointing out that when he develops alien abilities he’ll need their help to learn control.