Moos Linnemann had a long amateur career, contesting over 100 bouts before turning professional in December 1954. During that period, Linnemann won the 1948 Dutch featherweight title and the 1950 welterweight crown. Competing in two Olympic Games, he was eliminated in the first round in 1948, but won two fights in 1952 before losing in the quarter-finals. As a professional, he fought as “Nick Moos”, and contested 16 fights, most of them in the Netherlands. Linnemann won 15 of them, losing only his final bout. After retiring from boxing in 1957, Linnemann owned a flower boutique in Amsterdam until his retirement.
Netherlands