Doyle is the editor of the Yale Daily News and later Paris' boyfriend. Paris and Doyle meet through the newspaper, however they bond through a speed-dating session that Terrance had suggested Paris attend to help her cope with Asher's death. Doyle and Paris end up sleeping together that day.
Their relationship has its ups and downs, but in general Doyle seems to be able to handle Paris' temper and survives in one piece. After one falling out (after Honor's wedding), a drunk Doyle tries to kiss an equally drunk Rory, as he was drunk enough to think she was Paris for a moment, but she pulls him back to reality. Doyle goes back to Paris that night and argues in defense of their relationship.
A year later, he has to defend their relationship again when Paris tries to break up with him so as to not have to consider him in her plans for the future. With the understanding that Doyle is happy to follow whatever decision Paris makes, she takes him back, and they enjoy a long-term relationship that continues through past the end of the show.
Doyle and Paris live with each other after the relationship becomes serious. After a while, Paris invites Rory to join them.