After attending the Jesuit Convocation in Neuhaus (Bohemia), he studied at the German College of Apollinaris in Rome and received his doctorate in theology.

The Prince-Bishop of Passau, Raymund Ferdinand von Rabatta, tried to prevent this, but on 6 March 1721, the Congregation in Rome agreed, and on 1 June 1722, the decision of the Consistory of Cardinals followed.

On 14 February 1723, was that of Pope Innocent XIII in signing the Papal Bull Suprema dispositione, finally elevating Vienna.

He was elevated to the cardinalate by Pope Benedict XIII on 26 November 1727, and at the same time appointed cardinal-priest of Santi Marcellino e Pietro, in 1740 Kollonitsch changed to the titular church and became cardinal priest of San Crisogono.

He appointed him heir to his dominions with the condition that he and all his descendants, with the complete omission of their former name and coat of arms, should be addressed only as Counts and Countesses von Kollonitsch.