Koželuh had already beaten Vinnie Richards to win the United States Pro Championship in 1929. He went on to win the title again in 1932, defeating the German Hans Nüsslein, and in October 1937, beating the American Bruce Barnes at The Greenbrier in West Virginia at the age of 42. With this win, he became the oldest winner of a major professional singles tournament. In the first round at the Greenbrier tournament in 1938 (not classed as the US Pro this year), Koželuh faced Greenbrier golf professional Sam Snead, beating him in three straight sets. Koželuh was the losing finalist at the US Pro in 1928, 1930, 1934 and 1935. Koželuh was a six-time winner of the Bristol Cup (Menton, France), which was the most prestigious professional title in the world in the 1920s. He also won the World Pro tournament in Deauville, France, in 1925. Another major title for Koželuh was the French Professional Championship of 1930.