Aunt March, the paternal great-aunt of the March sisters and estranged sister-in-law to their father, initially presents a cold and severe demeanor. Old grudges against George March fuel her reluctance to offer his family temporary refuge at her Newcord estate after the Civil War destroys their home. She maintains her sternness, particularly toward Jo's unconventional, tomboyish behavior. Her nephew, the indebted gambler David Fowlet, antagonizes the Marches, fearing displacement as her heir.

Gradually, Aunt March develops an attachment to her nieces, though she rarely shows open affection. Her bond with Amy deepens significantly when Beth contracts scarlet fever; sent to Aunt March's to avoid infection, Amy's admiration for the elderly woman's wealth and jewelry, coupled with her better manners, wins her favor. This leads Aunt March to select Amy as her companion for a European tour, highlighting her growing favoritism.

Her character evolves further: she disinherits David for financial recklessness and reconciles with George March upon his return from war. Beneath her severe facade lies a capacity for kindness, demonstrated through practical support like offering financial aid for Marmee's trip to Washington when Mr. March is injured (though declined). Her latent familial loyalty surfaces through these subtle acts of care.

The anime adaptation enriches her household environment with original elements: additional servants like Ben the coachman and Dorothy the cook, and pets beyond Polly the parrot, including a poodle named Harry, without altering her core traits of initial austerity.