Aged 18, Halvorsen captained and scored for his hometown club Sarpsborg in their 1917 Norwegian Cup final victory, beating Brann Bergen 4-1. ราคามวยสด
During those amateur days he was working as a ship broker. An opportunity came to move to Germany's north coast.
He joined Hamburg and was an immediate success - Halvorsen led the club to two German championships and eight regional north German championships.