Hayato is a popular guy in the same class as Hachiman and Yui.
Hayama Hayato serves as a foil to Hachiman’s character being almost the opposite in many areas on the surface: popular, kind, smart (ranked 2nd in Literature, just behind the rank 1 Yukinoshita and just ahead of the rank 3 Hachiman), athletic (he is the soccer club’s ace and captain, and Totsuka stated that of the entire school, only he would be able to obtain an athletic scholarship. In addition, he won the school marathon each time he competed, even when handicapped by Hachiman wasting his time and reducing his lead), and in general more personable, optimistic, and agreeable. Many characters look to him as a leader figure or look up to him as a model student.
Under the surface however, Hayama appears to have some internal turmoil coming to grips with events in his past and how to maintain his relationships in the present. He admits openly to Hachiman that he is “jealous” of Hachiman and that he feels an inferiority complex toward him. He also says that he dislikes Hachiman, but unlike other students, he has always treated Hachiman fairly and respectfully, refraining from insulting him, unlike some other students. He even defends Hachiman on multiple occasions and has even teamed up with him in issues such as the judo tournament, during the school festival, during the summer camp, and numerous other events.
He and Yumiko are the central figures in their clique, and he has a crush on someone whose name begins with “Y”.