Laurie, formally Theodore Laurence, is the wealthy grandson of the March family's neighbor, Mr. Laurence. Initially lonely and confined under strict supervision, he forms a close bond with the March sisters, especially Jo. Her spirited, unconventional nature resonates with his own rebellious tendencies against societal expectations, encouraging him to embrace a more carefree and expressive personality. This friendship fosters his love for music and creative pursuits over conventional business aspirations.

Following Jo's rejection of his marriage proposal, Laurie travels to Europe at his grandfather's suggestion. He initially indulges in self-pity but gradually matures through interactions with Amy March. Her practicality and sensibility help him recognize their compatibility, leading to their marriage. This union stabilizes Laurie, transforming him into a devoted family man who finds a sense of peace previously absent.

In later years, Laurie is established as a prosperous and influential figure, having inherited considerable wealth. He and Amy reside in a grand mansion and maintain a secondary holiday home. They have one daughter, Bess, noted for her artistic inclinations and refined demeanor. Laurie uses his resources generously to support the educational and professional endeavors of Plumfield's students, including Nat Blake and Dan Kean, often providing financial backing without expectation of repayment.

Laurie remains connected to the extended March family and the Plumfield community. He attends significant events, such as the funeral of his former tutor John Brooke, Meg March's husband. His presence is also noted during social gatherings, including dances hosted at his estate, Parnassus, where he interacts warmly with the younger generation of Plumfield students. His guidance and encouragement extend to his niece Josie Brooke in her acting aspirations, reflecting his ongoing role as a supportive family patriarch.