Margaret "Meg" March, eldest of the four March sisters, is sixteen and acutely remembers her family's former wealth before genteel poverty followed her father's financial losses. This memory fuels initial resentment toward their circumstances and a longing for luxury, fine clothes, and a life free from labor. She prides herself on her beauty, especially her smooth white hands, and dreams of marrying into wealth to regain comfort and status. Despite these materialistic desires, she shoulders responsibility as the eldest daughter, helping her mother manage the household and care for her younger sisters while their father serves as a Civil War chaplain. To support the family, she works as a governess for the wealthy King family, disliking the constant reminders of the luxury she lacks.

A pivotal moment occurs during a two-week stay with the wealthy Moffat family. Eager to fit in, Meg allows them to dress her extravagantly for a ball, complete with borrowed finery and excessive makeup. This crumbles when she overhears gossip labeling her a fortune hunter targeting their neighbor Laurie, and when Laurie himself disapproves of her artificial appearance, comparing her to a "doll." Humiliated and disillusioned, Meg recognizes the superficiality and moral emptiness of the wealthy circle. She returns home chastened, confesses her mistakes to her mother, Marmee, and resolves to value authenticity and simplicity over wealth and appearances. This marks the beginning of her maturation, though she continues to struggle occasionally with envy and vanity.

Her character deepens through further trials. During her mother's absence to care for their wounded father, Meg helps manage the household and nurses her sister Beth through severe scarlet fever. Beth's illness profoundly impacts Meg, shifting her focus from material desires to gratitude for intangible blessings like health, family love, and peace. Her returning father observes her transformation, noting her once-prized hands are now hardened and marked from work – a physical sign of her growth, resilience, and embrace of domestic duty.

Meg's romantic storyline centers on John Brooke, Laurie's poor but virtuous tutor. Initially hesitant due to his lack of wealth and her own dreams of grandeur, Meg eventually accepts his proposal after recognizing his integrity, hard work, and deep devotion. Her parents require them to wait until she is twenty to marry, ensuring maturity. Their wedding is intentionally simple and modest, reflecting Meg's changed values; she wears a self-made dress with flowers in her hair instead of jewels, signifying acceptance of a life built on love and shared effort.

Marriage and motherhood present new challenges. Early financial struggles surface when Meg overspends on expensive silk fabric, straining their budget and causing John hardship. This forces a difficult but honest conversation, strengthening their bond as they learn mutual understanding and the true value of shared sacrifice. They establish a humble home where Meg strives to be a capable housewife and mother. After the birth of her twins, Margaret "Daisy" and John "Demi" (later followed by Josie), Meg initially struggles, becoming so absorbed in motherhood she neglects her husband and household duties. With Marmee's guidance, she learns to balance her roles, prioritizing her relationship with John alongside caring for the children, reinforcing her appreciation for partnership and the sustained effort required for domestic harmony.

Despite fully embracing her role as wife and mother, Meg retains a lingering appreciation for beauty and comfort but no longer envies the idle luxury of acquaintances like Sallie Moffat. She finds genuine fulfillment in her family life and the modest, industrious home she builds with John. Her ultimate contentment is expressed in her reflection that her childhood "castle in the air" has been realized not through riches, but through a loving husband, children, and a simple, happy home – making her "the happiest woman in the world."