While he was still training, director Oscar Fritz Schuh brought him to the Deutsche Schauspielhaus Hamburg, where he made his debut in 1963 in Molière's The Imaginary Invalid.
In 1964, he was at the Schauspielhaus Bochum, then moved to the Bühnen der Stadt Köln for the following four years, and from 1968, he worked for the Bavarian State Theater.
From 1973 to 2001, he was a permanent ensemble member at the Münchner Kammerspiele, before returning to the Bavarian State Theater for the 2001/02 season.
In addition, Hamel took part in guest engagements at the Salzburg Festival and at the Vienna Burgtheater.
Hamel has also acted in numerous film and television productions, as well as reading audio books and dubbing.