Who was the main proponent of Utilitarianism?

The main proponent of Utilitarianism was Jeremy Bentham, an English philosopher and social reformer. He is best known for introducing the principle of "the greatest happiness for the greatest number," emphasizing that the moral value of actions is determined by their outcomes in promoting overall happiness. Bentham's ideas were later expanded by John Stuart Mill, who further developed the theory and addressed its implications for individual rights and justice.