Sergey Bulygin won his first international medals at the 1982 World Junior Championships, where he won silver in the relay and bronze at 15 km. This bronze would remain Bulygin’s only individual medal at an international championship, as he won relay gold at the 1984 Olympics, was World Champion in the relay in 1983, 1985 and 1986 and World Champion in the 20 km team event. At the 1989 World Championships he also won a silver in the relay. His best individual finish at a major international after 1982 was sixth in the 20 km at the 1983 World Championships. After his sporting career Bulygin worked as a biathlon coach in Belarus and Switzerland and later became advisor to the Belarus President for sports-related matters.