He made his Olympic debut at the 2004 Games in Athens, Greece. Competing in the men's individual foil. He received a bye in the first round, beat China's Wang Haibin in round two and Dan Kellner of the United States in the third round before being defeated 8–15 by Andrea Cassarà in the quarter-finals. His eighth-place finish was the best by a British fencer since the 1992 Summer Olympics in Barcelona, when Fiona McIntosh was eighth in the women's foil, and the best by a British man since the 1964 Summer Olympics in Tokyo, when Bill Hoskyns won the silver medal in the individual épée. In 2006 Kruse won the silver medal in the men's foil event at the European Fencing Championships.