Amy March, youngest of the four March sisters, begins the story at twelve as a somewhat spoiled and attention-seeking child, prone to vanity and melodrama. She longs to fit into high society and escape poverty, often coveting fine things and chafing against the family's financial limits. Early actions include trading pickled limes at school, leading to punishment, and burning her sister Jo's manuscript in revenge when excluded from a theater outing, causing significant familial conflict and temporary estrangement from Jo. A later impulsive act—trying to follow Jo and Laurie skating—results in her falling through ice, a near-tragedy reinforcing the consequences of such behavior.

Physically, she starts as a slender, pale child with blue eyes and shoulder-length blonde hair, often in braids. Maturing into "the flower of the family," Amy develops an air of grace, her golden hair becoming more abundant and her bearing dignified. Her childhood concern with appearance includes nightly use of a clothespin to reshape her nose, a habit fading with age. As an adult, she carries herself stately and favors simple yet elegant clothing.

Artistic ambition is central to Amy. She declares her wish to "be an artist, go to Rome, do fine pictures, and be the best artist in the whole world." She experiments tirelessly across mediums—pen-and-ink, charcoal, oil painting, sculpture—enduring mishaps like scarring her foot during a failed plaster casting attempt. Though enthusiastic and persistent, she eventually confronts her limitations, acknowledging "talent isn’t genius." She channels this artistic sensibility into refined appreciation, continuing to paint seriously throughout life while shifting focus from professional greatness.

Forced separation during Beth's scarlet fever outbreak marks pivotal growth. Sent to live with Aunt March, Amy navigates exile pragmatically, learning to leverage charm and social grace. Later, accompanying Aunt Carrol to Europe instead of Jo, she studies art and cultivates societal polish, broadening her worldview and accelerating maturation into a poised, self-assured woman.

In Europe, Amy reconnects with childhood neighbor Theodore "Laurie" Laurence. Initially critical of his idleness after Jo rejects his proposal, she challenges him to find purpose. Their bond deepens through candid conversations about art, societal expectations, and disappointments. Amy articulates a pragmatic view of marriage as an economic necessity for women without means, explaining her initial acceptance of wealthy Fred Vaughn's proposal—a decision reversed upon recognizing the emotional void it promised. She ultimately marries Laurie, forging a partnership based on mutual growth, affection, and complementary temperaments: her grounded practicality balances his free-spirited nature. They name their daughter Elizabeth "Bess" after Amy's late sister.

Amy's personality evolves significantly from childhood self-centeredness to principled adulthood. Early attempts at generosity or moral improvement stem from a desire for admiration rather than intrinsic virtue. She develops genuine empathy, resilience, and nuanced understanding of responsibility. While retaining ambition and appreciation for refinement, she prioritizes family loyalty and emotional integrity, evidenced by rejecting Fred Vaughn and supporting Laurie steadfastly. Her clear-eyed assessment of societal constraints, artistic potential, and personal relationships reflects hard-won wisdom.