Kyle's Buddhism is often used as joke fodder, with him often quoting philosophical texts to help in serious situations, to the exasperation of his father, Sheriff Jim Valenti, and friends.
At the end of season one, his father doesn't return home and an FBI agent is put in front of his house to keep a watch out.
He takes a gun from his father's cabinet and follows Max to the UFO Center, where he finds Agent Pierce, whom he believes to be the innocent Deputy Fisher, tied up.
He wants nothing to do with the "little green men" and at first, does not join them in their main adventures, but finds one as a roommate when the orphaned Tess Harding moves in with him and his father.
After this, Kyle is reluctant to help the group but does so anyway when they are searching for a cluster of toxic crystals that could spell doom for the world.
After this encounter, Kyle once again grows friendly with the entire group, including Max, and becomes a substantial member of the alien clique.
At the end of season two, Kyle sees off Tess when she, Max, Michael and Isabel are forced to go back to their home planet, Antar.
Max, Michael and Isabel exit the chamber as Tess returns to Antar, and Kyle stands with his five friends in the closing moment of the season, having gone from being an antagonist to a trusted member of the group.
With Tess gone and Alex dead, Kyle and Isabel are the only two members of the group of six who are not romantically involved with another, and end up spending a lot of time together, becoming close friends.
An honorable man, he keeps these feelings inside, but is henceforth shown as deeply caring for Isabel, breaking down crying at her bedside when she is shot and almost killed.
In the series finale, "Graduation," when the rest of the group is forced to leave Roswell and live on the run, Kyle makes the decision to come with them, citing that he wants to be with his "own kind" when he starts to "snap, crackle and pop like tin foil".
He is last seen in the series with the other five main characters as they celebrate the wedding of Max and Liz and once again board the van, continuing on their road trip across America.