Despite his aversion to needles, Harrison persisted in his altruistic endeavors. His grandson, Jarrod Mellowship, spoke to the media about his grandfather's dedication to donating, stating, "He just kept going because he wanted to help." Harrison's plasma contained a unique antibody known as anti-D, crucial for creating a therapeutic solution that prevents pregnant women from developing antibodies that could attack their babies' red blood cells. This groundbreaking therapy has been integral in preventing severe medical issues arising from Rh incompatibility during childbirth.

Harrison died peacefully at a nursing home one hour from his regular donation site in Sydney, leaving behind a profound legacy celebrated by many. His enduring spirit and commitment to saving lives will be remembered by the medical community and the families he has impacted throughout his lifetime.