Lehmann was born in Königsberg in 1921, studied law. As a chess player, he received FIDE title, International Master (IM) in 1961. He won 1956 Berlin City Chess Championship and 1976 European Chess Club Cup. He was a national player in the 1950s and 1960s, took part in the 13th and 14th Chess Olympiad. He played for West Germany in the 1957 European Chess Championship, and won the individual bronze medal for his board.