Maggie is introduced in the 23rd episode of the
tenth season of ''Grey's Anatomy'', during
Cristina Yang’s search for her replacement as the head of
Cardiothoracic Surgery. Maggie, a prodigy who finished high school and medical school by the age of 19, became the head of her department at 27. In the Season 10 finale, titled “
Fear (Of the Unknown)”, it is revealed that Maggie’s biological mother is Ellis Grey, making her the half-sister of
Meredith Grey.
Richard Webber, who had an affair with Ellis, is stunned by the news, realizing that he is Maggie's biological father. Throughout
Season 11, Maggie navigates her new role at Grey Sloan Memorial Hospital while dealing with her complicated family history. When she discovers that Meredith is her half-sister, she attempts to bond with her, but Meredith initially resists. The revelation of their shared parentage causes friction between them, but eventually, Meredith and Maggie come to terms with their relationship. At the same time, Richard struggles to reconcile with the fact that he has a biological daughter he never knew about. Maggie, who had previously discovered Ellis’ identity while searching for her birth mother, is initially hurt and confused by Richard’s behavior but later forgives him for not being there for her growing up. The two gradually develop a father-daughter bond. Maggie also develops friendships with her colleagues, including Meredith,
Alex Karev, and
Callie Torres. As Maggie integrates into her newfound family, she becomes a maternal figure to Meredith’s children after Derek’s death in season 11, and she, Meredith, and
Amelia Shepherd form a “sisterhood” of sorts, sharing responsibilities in caring for the kids. Maggie helps mediate the frequent conflicts between Meredith and Amelia, further solidifying her role in the Grey family. In
Season 12, Maggie begins a relationship with intern
Andrew DeLuca, but they keep it a secret to avoid complications at work. However, their relationship becomes strained due to the secrecy, and DeLuca eventually ends things. Maggie later develops feelings for
Nathan Riggs, unaware that Meredith has already started a relationship with him. This causes tension between the two sisters, especially when Maggie confesses her feelings to Meredith, who hides the truth from her. The rift between Maggie and Meredith intensifies when Meredith continues to lie about her relationship with Riggs. In
Season 13, Maggie’s personal life is further challenged when her mother, Diane, comes to Seattle for treatment. Maggie is devastated to learn that her mother has terminal cancer. Diane’s death profoundly affects Maggie, who begins to reevaluate her life outside of work.
Jackson Avery supports her through her grief, and the two grow closer, eventually developing romantic feelings for each other. In
Season 14, Maggie and Jackson begin a relationship after initially trying to suppress their feelings. In
Season 16, after her breakup with Jackson, Maggie faces one of the biggest challenges of her career when her cousin, Sabi, dies during surgery. This tragedy causes Maggie to question her abilities as a surgeon, leading her to quit her job at Grey Sloan Memorial. Her depression worsens when Sabi's family sues her for
medical malpractice, but with Richard’s support, Maggie settles out of court and eventually rejoins Grey Sloan. In
Season 17, Maggie reconnects with Winston Ndugu, a former colleague, at a medical conference, and they begin a
long-distance relationship. As the
COVID-19 pandemic hits, Winston surprises Maggie by traveling to Seattle to help at the hospital, and their relationship deepens. Winston proposes to Maggie, and they marry in the season 17 finale. ==Development==