Kosour was born in Radňovice. He was a member of the national Olympic military patrol team in 1936 which placed eighth. He also took part at the 18 km cross-country ski and the Nordic combined event of the 1948 Winter Olympics. In a row from 1939 to 1942 and in 1949 he placed first at the Zlatá lyže ("Golden Ski") cross-country ski race in his hometown, which was primarily carried out for the first time in 1934.