Josephine "Jo" March is the central protagonist in animated adaptations of Louisa May Alcott's stories. Introduced at fifteen as tall, thin, and physically awkward, she possesses sharp grey eyes and long brown hair, later cut short and sold to fund her mother's urgent trip. By eighteen, her appearance matures into a composed young woman with restored hair and graceful bearing.

Spirited, independent, and tomboyish, Jo openly rejects conventional femininity, chafing at domestic limitations. She prefers running, climbing, and writing. Her volatile temper, acknowledged as a "fatal flaw," gradually comes under control through experience and her mother's guidance. Academically and creatively driven, she immerses herself in literature and writing, crafting plays and stories. She pursues publication but abandons sensational fiction when it conflicts with her morals. She works as a companion for her critical Aunt March and later as a governess in New York.

Family profoundly shapes her. She shares a deep bond with her sisters, especially the gentle Beth. Beth's terminal illness compels Jo to embrace caregiving, fostering previously suppressed tenderness and highlighting the value of domestic devotion. Conflicts arise with her youngest sister, Amy, notably when Amy destroys Jo's manuscripts, though they reconcile after a life-threatening accident. Her pivotal friendship with neighbor Theodore "Laurie" Laurence involves shared mischief and intellectual exchange. She rejects his marriage proposal, viewing him only as a brother, due to her aversion to romance and awareness their temperaments would clash.

Seeking independence, Jo moves to New York as a governess. There, she meets her German language instructor, Professor Friedrich Bhaer. Their friendship deepens through philosophical discussions; he indirectly influences her to stop writing sensational fiction. Returning home to care for Beth, Jo later receives and accepts Bhaer's marriage proposal. Inheriting Aunt March's estate, Plumfield, they establish a progressive coeducational school. As depicted in sequels, she balances managing the school with raising her two sons, Robin and Theodore. Her educational philosophy emphasizes kindness, play, and moral guidance, welcoming orphans and nephews. While embracing motherhood and teaching, she maintains her energetic spirit, occasionally showing impatience or joining students' adventures.

Her core identity as a writer persists. Early ambitions for fame evolve into chronicling family experiences and crafting moral stories for her students, integrating her literary passion with her roles as educator and matriarch.