Birlenbach finished fifth at the 1966 European Championships, eighth at the 1968 Summer Olympics and seventh at the 1972 Summer Olympics, the latter in a career best throw of 20.37 metres. This places him 26th on the German all-time list. He also won the 1968 and 1969 European Indoor Games, the latter in a new championship record of 19.51 metres. He became German champion six times in a row, from 1966 to 1971. He competed for the sports club Sportfreunde Siegen during his active career.