Naomi is the main character of Obasan and the story's narrator. She struggles with painful memories of her past and chooses not to think about them. Her resolve is broken, however, when her uncle's death revives those memories, and a packet of letters and documents collected by her aunt reveals details that she was unaware of before. Naomi was raised to believe that it is better to hide grief in silence than burden others with one's sorrow, and that shame is best kept a secret. For that reason, she kept an episode of childhood abuse secret from her family and became somewhat silent and serious as a result. The silence of other family members also adds to her pain, since they continually hide unpleasant information from her—her father's illness, for example, and the fate of her mother. The adults do not even acknowledge the horror of their internment, adding to Naomi's confusion and her feeling that the past should be ignored. Only when her Aunt Emily forces her to deal with the past and the fate of her mother is revealed does Naomi begin to heal.
Obasan Ayako Nakane
Obasan is Uncle Isamu "Sam" Nakane's wife. After two miscarriages, she has no children of her own, but she and Uncle raise Naomi and Stephen during the Japanese Canadian internment period of World War II and continue to raise the children after the deaths of Naomi and Stephen's parents. Obasan is a quiet, stoic woman who honors tradition and feels it is her responsibility to suffer hardship and grief in silence. She is incredibly strong, however, shouldering the burden of caring not only for the children, but for an invalid who is given into her care. But her selfless heroism eventually takes its toll, and Naomi watches her "turn to stone," trapped in her own silence.
Aunt Emily Kato
Aunt Emily is Obasan's exact opposite. Where Obasan is silent, Emily talks constantly. Where Obasan refuses to dwell on the negative aspects of her life, Emily fights against injustice and insists that people confront the evils in the world. Emily does not at all match the traditional image of a proper Japanese woman. She speaks at conferences, writes letters to Canadian representatives, and argues passionately for better treatment and reparations for the Japanese Canadians who were forced from their homes. Aunt Emily is also the constant voice pushing Naomi to remember and deal with her childhood trauma so that she can move past it. She believes that the past defines who we are, and also informs the future.
Stephen is three years older than Naomi. He loves music and played often with Mother and Father. As the older sibling, he understands more of what is happening to Japanese Canadians than Naomi does and, as a result, suffers more that she does from the persecution. His reaction, though, is to turn on his family and his heritage, and to focus on what will best help him become part of white society. As an adult, he becomes a successful concert pianist, but he cuts himself off from anything that reminds him that he is Japanese—including his family.
Uncle Isamu Nakane
Uncle is Grandma Nakane's son by her first husband, and Obasan's husband. He is also the older brother Mark Nakane, Naomi's father. Uncle is a kind man, a good husband, and a father figure to Naomi and Stephen. He is a respected boat builder until the internment period, when his ships are confiscated, and he is no longer allowed to practice his profession. But he retains a positive energy and optimistic outlook, preferring to focus on what he can do to improve his family's life. When he joins them in the internment camp, he immediately sets about improving their home. Years later, he puts the suffering behind him, still proclaiming that Canada is the best place in the world to live.