Internationally he placed eleventh in the 10,000 metres at the 1958 European Championships and 26th in the marathon at the 1960 Summer Olympics in Rome. On the track he became Norwegian champion in the 5000 metres in 1959 ahead of Reidar Andreassen and Pål Benum. He also won silver medals in 1956, 1958 and 1960 and a bronze in 1955. In 1959 he also won the national 10,000 metres title. He broke a Trondheim dominance of more than decade, with Martin Stokken, Øistein Saksvik and Ernst Larsen having won all titles but one since 1947. In this event, Torgersen also won a national silver medal in 1957.