Thomas Gunst and the West German male field hockey team won the silver medal at the 1984 Los Angeles Olympics, losing the final against Pakistan 2-1 after extra time. The team also lost the 1982 World Cup final 3-1, again against Pakistan. In 1984 and 1988 he won the European Indoor title, and in 1983 won a bronze at the European Championships. In 1986, he was on the team that won the Champions Trophy. He won 70 international caps (including 24 indoor) between 1980-88.
Domestically, Gunst played with Dürkheimer HC and TG Frankenthal, helping them to win the West German Indoor title from 1982-84, and the West German Championship in 1983. The team then won the European Champions Cup in 1984. By profession, Gunst became a post office clerk.