After working as a journalist with La Meuse newspaper, Damseaux served on the council of Verviers, beginning in 1965.
In 1981 Damseaux joined the Walloon government, as Minister for External Relations and supervision of municipalities.
The same year he began service as the Minister for National Education in the federal government, and in 1982 served as Minister-President of the Walloon Region.
However, after suffering protests over his school reforms, Damseaux resigned from his Minister for National Education position on 9 March 1987.
[1] On 29 March 2007 Damseaux died in a Verviers hospital after suffering from a stroke.