Erny Kirchen began his cycling career by winning the youth road race title at the 1965 Luxembourg national championships. During the late 1960s and early 1970s Kirchen had success at the Flèche du Sud stage race, winning five stages, as well as the overall classification in 1973. One year earlier he competed in the road race at the 1972 München Olympics, placing 27th in a group of riders who were only 36 seconds behind the winner. Outside of his native Luxembourg he also won two stages at the 1973 Tour de l’Avenir in France, and then turned professional one year later. Although Kirchen did not have any victories as a professional, he did place second in the road race at the national championships, in addition to riding in the Vuelta a España. His son Kim was also a cyclist who competed at two Olympics.