The West German field hockey team at the 1956 Melbourne Olympics earned a bronze medal by winning the deciding game against Great Britain 3-1. In the semi-finals Germany had lost 0-1 to India. Helmut Nonn, brother of Wolfgang Nonn, played for Uhlenhorst Mülheim domestically and also participated in the 1960 Olympic tournament, where the team finished in seventh place. From 1956-64 he claimed 50 international caps. In 1956 he was awarded the Silver Bay Leaf.
With Uhlenhorst Mülheim Nonn won the West German Championships in 1954, 1955, 1957, 1958, 1960 and 1964. From 1981-88 he was president of his club and in 1989 became its honorary president.