During the Nazi era, he was active in the anti-Nazi resistance, and was imprisoned from 1936 to 1939 as a political prisoner.
After the war, he became a member of the SPD again and became active in the IG Metall union.
He was elected chair of the works council of AG Weser, his employer, in 1951, and served in this capacity until 1979.
The election of Böhrnsen, a social democrat, to this position, meant the communists were finally ousted from influence in the works council.
This biography article about a member of the Social Democratic Party of Germany (SPD) is a stub.