Arto Nilsson’s first international tournament was the 1968 Olympics, where he surprised everyone by reaching the light-welterweight semi-final where he lost to eventual Polish gold medal winner Jerzy Kulej and won a bronze medal. In 1970, Nilsson won the Nordic Championships in welterweight and also competed at the 1971 European Championships, where he lost his first round bout. Domestically, Nilsson was the Finnish welterweight champion in 1970 and 1971 and took bronze in 1972. After finishing his boxing career in 1972, Nilsson founded the Timanttiset Group that has become the leading Finnish retailer and importer of watches, jewelry and giftware. Nilsson was selected to the Finnish Boxing Hall of Fame in 2008.