Rainer Seifert won 122 international caps 1969-80, quitting after the West German boycott of the 1980 Olympics. In addition to his Olympic gold in 1972, Seifert won a bronze medal at the 1973 and 1975 World Championships, and was on the gold-medal winning team at the 1978 European Championship, and 1974, 1976 and 1980 European Indoor Championship.
Domestically, Seifert played from 1968-80 for Rüsselsheimer RK and helped them win the West German Championship five times in 1968, 1971, 1975, 1977-78, and also the national indoor title in 1973, 1976 and 1978. Like team-mates Peter Kraus and Michael Peter, Seifert spent his entire working life with the German car manufacturer Opel.