Dirk is Nick's roomate from law school. He is a degree collector, and the smartest guy Nick knows.
Dirk is introduced when Jess walks in on him at the urinal "Tony the Tiger style." He went to law school with Nick, and has a tendency to stay in college and accumulate multiple master degrees.
He was once married, but his wife left him after getting tired of financially supporting him. He uses his status in the education to hit on and hook up with young college women. He led Nick to a similar path, stating that Nick must find his "panty melter." Nick's job as a bartender appealed to college girls as he could "get them drunk professionally."