Paavo Nurmi of Finland with 12 Olympic medals (9 gold, 3 silver) in the 1920, 1924, and 1928 Summer Games.
He won 2 gold in 10000 meter run, 1 gold and 2 silver in 5000 meter run, 1 gold in 1500 meter run, 2 gold in team cross-country, 2 gold in individual cross-country, 1 gold in team 3000 meter run, and 1 silver in 3000 meter steeplechase.