Kyousuke Natsume is the leader of the Little Busters, a dependable older-brother figure who cares deeply for his friends. He loves playing around and pulling pranks, but he values his comrades above all else. While he often surprises everyone with his bold actions, he is a man who gives his all to protect the bonds of the group.

Rin Natsume is the heroine of Little Busters and Kyousuke's younger sister. She is shy and socially awkward, but kind-hearted and devoted to her friends. She loves cats and is almost always seen with one. Though she struggles to express her feelings honestly, she gradually grows through her interactions with the group.

Riki Naoe is the protagonist of Little Busters, a boy with a gentle and honest personality. Having lost his parents at a young age, he became part of the group after meeting Kyousuke and the others. While he dislikes conflict and cherishes his friends, he faces hardships through their bonds and gradually grows stronger.

Masato Inohara is the muscle of the Little Busters, a hot-blooded and simple-minded mood maker. As Riki's best friend, he spends his days rowdily with Kyousuke and the others. He loves muscle training and muscles above all else and is poor at studying. Despite his frequent foolish behavior, he is a man of deep friendship who cares for his comrades.

Kengo Miyazawa is the kendo practitioner of the Little Busters, possessing a serious, proud, and caring personality. His kendo skills are top-tier, and he has a calm judgment and a strong sense of responsibility. He is in a cat-and-dog relationship with Masato, often competing with him, but in truth, he values the time spent with his friends more than anything.