Josef Kasel was born in Dortmund as the youngest child of a family who stemmed from Trier.

He bacame a member of the so-called “Winzen Group”, a Resistance group based in Dortmund and named after one of its co-founders, Paul Winzen.
Created already before 1933, the group met secretly at changing locations during the time of the Nazi regime, printed and distributed leaflets expressing criticism of the regime, and listened to foreign radio stations.

In the course of time, however, the group was infiltrated by an informer, resulting in the arrest of numerous group members.

In February 1942, Josef Kasel was found guilty by the Volksgerichtshof, the so-called “People’s Court”, in Berlin of “subversion of the national defence capability” and “preparation of acts of treason”, and sentenced to death. On 12 June 1942, he was executed together with Paul Winzen (see the Stolperstein for Steinstr. 42) in Berlin-Plötzensee.