Kohn played as a striker, and spent most of his career plying his trade abroad, in Germany, Switzerland, and finally Netherlands, where he later became a successful manager.

Kohn made his debut for Luxembourg in a September 1953 World Cup qualification match against France, in which he immediately scored a goal.

Kohn moved on to Go Ahead Eagles in 1980 and Club Brugge in 1981 before rejoining Twente in the 1982/1983 season, but he could not save them from relegation that year.

After the firing of coach Aad de Mos, Kohn was the responsible manager, the last 5 rounds of the 1984/1985-season, coaching Ajax to the Dutch championship, with players like Hans Galjé, Stanley Menzo, Sonny Silooy, Frank Rijkaard, Ronald Koeman, Gerald Vanenburg, Marco van Basten, Rob de Wit, John van 't Schip and John Bosman.

After 5 rounds in the 1988/1989 season Kohn became the responsible manager at Ajax, his assistant being Louis van Gaal.