The athlete who famously said, "I am the greatest" is Muhammad Ali. He declared this iconic phrase during his boxing career, which spanned from the 1960s to the early 1980s. Ali, known for his skill and charisma, often promoted himself with bold statements that captivated audiences. He is renowned not just for his athletic prowess in the heavyweight boxing division but also for his activism and contributions to social justice. His legacy endures in sports and culture.