Anna Fitzgerald is the protagonist of My Sister’s Keeper. Anna is a surprisingly mature 13-year-old girl who seeks a lawyer, Campbell, to earn her own medical emancipation, as she was born to provide medical donations (blood, tissue, and organs) to her older sister Kate (who suffers from APL, an aggressive form of leukemia with a low survival rate). Anna’s decision goes against her parents, Sara and Brian, and elicits a court hearing concerning issues that children are often protected from. However, Anna’s life of medical procedures for Kate’s sake has altered the way she views the world.

Anna’s actions in the first half of the novel frame her as a child who is tired of being used; her mother insists that she is seeking attention. However, as the novel progresses, it becomes clear that Anna is not a typical teenager. She doesn’t seem to mind medical procedures, and her relationship with her sister is exceptionally strong. There are times when Anna and Kate fight like typical siblings (with Kate sometimes being jealous of Anna), but they are mostly friendly. This bond is reinforced by Kate’s illness and the necessary isolation required to keep her from health complications.