As the youngest son of the master of the Shimada ninja clan, Genji lived a life of luxury and privilege. He had little interest in the family's illegal businesses, and although he excelled at and enjoyed his ninja training, he spent most of his time pursuing a playboy lifestyle. Many within the clan considered the carefree Genji to be a dangerous liability, and they resented his father for coddling and protecting him. Following the clan leader's untimely death, Genji's older brother, Hanzo, demanded that Genji take a more active role in their late father's empire. Genji refused, enraging Hanzo. The tension between the brothers built to a violent confrontation that left Genji on the verge of dying.
Hanzo believed that he had killed his brother, but Genji was rescued by Overwatch and the intervention of Dr. Angela Ziegler. The global force saw Genji as a potential asset in its ongoing operations to combat the Shimada clan. As Genji's injuries left him clinging to life, Overwatch offered to rebuild his body in exchange for his help. He was put through an extensive process of cyberization, which enhanced his natural speed and agility and augmented his superlative ninja skills. Transformed into a living weapon, Genji single-mindedly set about the task of dismantling his family's criminal empire.