Geppetto is an elderly, solitary woodcarver whose long-held wish for a child manifests when he discovers a fallen oak branch during a storm. He carves it into a marionette named Pinocchio. That night, the Oak Fairy grants his wish, bringing Pinocchio to life on the condition the puppet earns his humanity. Geppetto devotes himself as a nurturing father, selling his only coat to buy Pinocchio a spelling book. His workshop is filled with handcrafted toys, reflecting his trade.

When the puppeteer Sneeroff captures Pinocchio after episode 29, Geppetto embarks on a prolonged search with Charlie the Mouse, enduring repeated near-misses and peril, including a storm-induced shipwreck. Later, after Pinocchio returns, soldiers arrest Geppetto, branding him complicit in "dark magic" due to Pinocchio's actions protecting a forest. He is exiled to the harsh Devil's Island.

Stranded there with Pinocchio and Gina, a girl rescued from sacrifice, Geppetto is cared for by the two children as they survive together. Pinocchio and Gina vow to be siblings, forging a family bond with Geppetto in isolation. Rescued by their animal companions, the group returns to Europe near Christmas. Geppetto witnesses Pinocchio achieve his transformation into a human boy through a self-sacrificing act of curing ill children with a rare herb. The series concludes with Geppetto, Pinocchio, and their companions together on Christmas night.