Hayri Sezgin started wrestling as a teenager in Bulgaria. He emigrated to Turkey in 1978, where he competed for various İstanbul clubs. Still a junior, he won a silver at the 1979 Balkan Games. Throughout the 1980s, Sezgin was one of the top freestyle heavyweight wrestlers in the world, but he frequently ended up in fourth place, claiming that spot at the 1984 Olympics, as well as at three European Championships. But fortunately, Sezgin claimed several medals as well, winning the bronze medal at the World Championships in the year of his retirement (1990) and a silver (1989) and bronze (1985) at the European Championships. In 1987, he won a gold medal at the Mediterranean Games. Sezgin died of a heart attack while training young wrestlers at the age of 52.