Hamutaro is a male golden hamster, originally purchased from a pet shop and now living as a pet with his human owner. He possesses a naturally curious nature and a consistently cheerful, optimistic personality. Deep bonds of friendship connect him to a diverse group of fellow hamsters called the Ham-Hams. Within this group, Hamutaro frequently takes charge, initiating adventures and rallying the others to tackle problems and overcome challenges.

His deep affection and loyalty towards his owner are central to his character. This devotion becomes especially evident when his owner faces peril, such as in the events of the third movie where Hamutaro organizes and leads a complex rescue mission involving many Ham-Hams to save her after she becomes trapped. This mission, requiring navigation through significant obstacles, highlights his determination, resourcefulness, and readiness to take risks for loved ones.

Through numerous adventures with the Ham-Hams, Hamutaro consistently demonstrates a strong sense of responsibility for his friends. He actively mediates conflicts within the group and strives to maintain harmony. His interactions often involve discovering new things about the world, solving puzzles, and aiding other animals or hamsters in need. These experiences contribute to his gradual evolution from a somewhat timid newcomer into a confident, proactive member of the Ham-Ham community, recognized for his dependability and kind heart. Courage and the ability to inspire others mark his character development.