Ambrose Walnut is the youngest baby squirrel in the Walnut Squirrel family, joining parents Cedric and Yardley, older brother Ralph, and older sister Saffron. Small but energetic, he particularly loves jumping activities like puddle jumping after rain. His curiosity sparks playful adventures, such as when he and Crème Chocolate Rabbit attempted violin and cello after seeing older children play, instruments squeaking comically and making them briefly think they'd broken them.

He frequently engages in imaginative play, like pretending to run a supermarket with other babies; his excitement over a store selling "everything we want" even helped inspire a real toy shop in Sylvanian Village. His adventurous spirit and capacity for wonder shine during experiences like dreaming of flying through the sky on a whale's back with Crème at the seaside. When Ambrose felt sad about not climbing trees as well as Ralph, his father Cedric built him a specially scaled treehouse with a log ladder, swing, slide, and hammock he could manage alone. This treehouse became both a personal achievement and a social hub, where Ambrose hosted friends Poppy, Alfie, Henry, Jason, Crème, and Ryan for climbing, swinging, and pretend tea parties.

Across different stories, Ambrose learns through experiences, navigating temporary disappointments like musical difficulties or embracing pride during accomplishments like hosting successfully in his treehouse. His interactions highlight his place within the Sylvanian community through friendships with peers like Crème and family bonds, where father Cedric believes he will "go on and do great things" despite his size.