In 1685 Kollonitsch was appointed Bishop of Raab, or Győr, in Hungary, in 1686 he was named a Cardinal, with the title of Cardinal-Priest of Saint Jerome of the Slavs, and in 1688 he was promoted Archbishop of Kalocsa.
In 1685 Kollonitsch was appointed Bishop of Raab, or Győr, in Hungary, and gave up his diocese in Austria, where he was succeeded by Cristoval Royas de Spinola. In 1686 he was named a Cardinal, with the title of Cardinal-Priest of Saint Jerome of the Slavs, and in 1688 he was promoted Archbishop of Kalocsa.