Kengo is a member of the Little Busters. He is skilled in the art of kendo and seemingly has a cynical personality, but his passion for the Little Busters is unmatched by anyone. Kengo is recruited after Masato, Kyousuke and Rin defeat his father, making him the fourth member of Little Busters. Kengo gets into a disagreement with Kyousuke's method of strengthening Riki and Rin, which eventually proves to be too tough for Rin. In Refrain, when Rin breaks down mentally and Kyousuke's plan has backfired on him, Kengo tries to find a way so that they can keep living in the artificial world indefinitely rather than letting Riki and Rin face the harsh reality in the real word. The arm injury bandage he had in Refrain is a fake. However, after he is defeated by Rin in a baseball game, he realizes how strong Rin has become. He later regrets his action and breaks into tears, remembering how Kyousuke saved him from his eternal path of kendo by defeating his father, and rejoins the Little Busters. During the school excursion, he saves Rin in the real world during the bus accident.
Kengo has the second-highest starting strength and stamina, and unlike Masato, Kengo is also reasonably high on reflex and agility. He will not participate in the baseball game during first-time play through, limiting the team to eight members. Once he does participate, he can be a very valuable infielder, and if the player manages to record more than five-hundred hits during practice session before he joins the team, his skills during the baseball game will increase tremendously. For battle, he has a tendency to stack up stamina enhancing accessories (which, not surprisingly, are protective armor parts from his kendo club) so defense-wise, he can be quite resilient.