Question of the day #362, History

I am a retired American sportsman. I n the 1990s, I was crowned as "Sportsman of the Century".  I refused to serve the US army during the Vietnam war as war is against the teachings of Holy Koran. I have been married 4 times. In my  autobiography, I would have stated that I threw my Olympic gold medal into the Ohio River after being refused service at a ‘whites-only’ restaurant.

Who am I?