Following his secondary education and brief work experience, he enlisted in the Gold Coast Regiment in 1944. On January 20, 1951, Hansen was commissioned a lieutenant in the
Royal West African Frontier Force after a training course. In 1958, he became one of the first officers of the
Ghana Regiment, when the
Gold Coast gained independence. In 1960, he was made a grade II staff officer in the Office of the Chief of General Staff at the army headquarters. He was made responsible for organizing the expansion of the Ghana Army in 1960. Hansen was also appointed Secretary to the Chiefs of Staff Committee before being later appointed military assistant to the president. He consequently moved to the Flagstaff House to work as military assistant to
Kwame Nkrumah. In 1966, after Nkrumah's overthrow, the
National Liberation Council appointed Hansen as Chairman of its Greater Accra Regional Administrative Committee. In 1967, Hansen was re-assigned as Military Attache to Ghana's High Commission in Britain. In March 1970, he retired from the Ghana Navy with the
flag rank of Rear Admiral. ==Honours==