Muhammad Ali's original name was Cassius Marcellus Clay Jr. He was born on January 17, 1942, in Louisville, Kentucky, USA. He changed his name to Muhammad Ali after converting to Islam in 1964. Ali went on to become one of the most legendary and influential boxers in history, winning three heavyweight titles throughout his career. His legacy extends far beyond the boxing ring, as he was also an outspoken civil rights activist and philanthropist.