Mills has posted that her dad is Canadian and her mom is South Korean. Her sister Emma is just 15 months more youthful in age. She has distributed photographs of them praising their everyday life. They have lived as a family everywhere.
She has a powerful bond with her Korean family line, which she considers a source of pride and vitality. Her mother is responsible for her childhood immersion in Korean traditions, bizarre concepts, folktales, and children’s songs, as well as the way she prepared traditional Korean food at home and taught her the Korean language while encouraging her to read and compose. She expresses her heartfelt gratitude to her mother.