At the 1960 Winter Olympics in Squaw Valley , he won the silver medal behind Helmut Recknagel , and the bronze medal at the 1962 Nordic World Ski Championships in Zakopane . However, he was not able to receive this medal immediately after the competition (on the final day, February 25th), because the referee made a mistake and Peter Lesser was ranked 3rd and he was honored. When the error was discovered, Lesser had already left with the GDR team. Until the end of his active sports career in 1967, he often reached the top ranks, but was never able to win an international jumping. After the end of his career, Halonen worked in Finland as a functionary of the Finnish Ski Association, until 1992 as the coordinator of the FIS for the discipline of ski jumping; at the Nordic World Ski Championships in 1997 in Trondheim, he was a judge.