Eric Hänni was working as a toolmaker when he took up judo in his hometown of Delémont, Switzerland. From here Hänni became one of the best lightweight judokas in the country, winning his first of seven national titles in 1959. His best results came in 1964, with bronze at the European Championships in Berlin, followed by silver at the Tokyo Olympics. He competed at multiple international tournaments during his career including three World Championships and 12 editions of the European Championships. Hänni also worked as a judo referee and teacher, officiating in competitions across the world from 1965 to 1985. He opened his own judo school in 1972, working there until 1995, in addition to working as a coach to the national team. After a lifetime dedicated to the sport he was awarded with an honorary 9th dan in 2014, the first Swiss judoka to receive the title.