This article highlights important aspects of the biography of Giovanni Berlinguer that led him to become a prominent scientist and political activist. His works were marked by a strong socialist conviction and deep humanism. His contribution to health in Brazil ranged from a vast academic output in the field of public health to an active involvement in the Brazilian Health Movement. His later publications addressing everyday bioethics reveal the common thread that runs through his entire works: the use of science to demonstrate the social determinants of health; the fight against unjust inequality; the defense of life against exploitation; and the struggle to prevent the commoditization of life, the human body, and health care.