Retired Marine Lt. Col. Bill McMillan competed in six Olympic Games. The only Olympics he missed between 1952 and 1976 was in 1956 when his pistol misfired, costing him a spot on the team. McMillan competed only in rapid-fire pistol in the Olympics, winning it in 1960 and with his next best finish being seventh in 1952.
He won two world championships in free pistol and five golds at the Pan American Games, as well as four national titles at rapid-fire pistol and one at free pistol. His Pan American Games medals were the following: 1955 gold in 25 m rapid fire pistol team (with Joe Benner, John Forman, and the non-Olympian Thomas Mitchell) and 25 m centre fire pistol team (with Joe Benner, John Forman, and the non-Olympian John Jagoda) and silver in 25 m rapid fire pistol and 25 m centre fire pistol, 1963 gold in 25 m rapid fire pistol team (with Thomas Smith and the non-Olympians William Blankenship and William Mellon), 1967 gold in 25 m rapid fire pistol and 25 m rapid fire pistol team (with Edwin Teague and the non-Olympians Aubrey Smith and William Blackenship), and 1979 silver in 25 m rapid fire pistol and 25 m rapid fire pistol team (with John McNally, Darius Young, and the non-Olympian Terence Anderson). McMillan later worked as a sheriff for San Diego County, CA.