PapaPanda is a large, anthropomorphic panda with a round, soft physique and distinct black-and-white fur. His wide, consistent smile and simple expressions create an approachable look reminiscent of later Studio Ghibli characters. He balances a gentle, protective nature with childlike playfulness, often sliding down banisters or playing a tuba in musical parades.

He and his young son, Panny, escaped from a zoo seeking a home, finding Mimiko's house in a bamboo grove. There, they form an unconventional family: PapaPanda becomes Mimiko's adoptive father, and Mimiko becomes a mother figure to Panny. His primary drive is safeguarding this family. He demonstrates fierce protectiveness, like forcing shut a rusted floodgate to save Panny from dangerous waters, simultaneously preventing Mimiko from falling in. Later, he stops a runaway circus train threatening the mayor's house.

Despite living with Mimiko, he maintains an arrangement with the zoo, returning daily after visiting hours to fulfill his responsibilities while preserving family life. His interactions with humans beyond the family include collaborating with a zookeeper and local police during rescues, though his size and species initially cause alarm.

His protective instincts extend in the sequel to Tiny, a lost baby tiger the family shelters. During a severe flood, he helps locate stranded circus animals and aids community rescue efforts. The narrative concludes with PapaPanda fully integrated into daily life with Mimiko and Panny, frequently seen at community events like circus performances and engaging in playful musical parades at home.