[1] Wahlman was commissioned as an officer in 1899 and was assigned to Vaxholm Artillery Corps with the rank of underlöjtnant.

[3] Wahlman was a teacher at various times at the Royal Swedish Naval Staff College between 1908 and 1927 (including weapons science in the coastal artillery program[4]) and at the Royal Swedish Naval Academy between 1908 and 1925.

Wahlman served as expert in the commission concerning the organization of the army and navy air force from 1918 to 1922.

[1] Wahlman was promoted to major in 1920[1] and served as an assistant in the Artillery Department at the Royal Swedish Naval Materiel Administration.

In 1929, he was promoted to major general and appointed commander of the Swedish Coastal Artillery.