[2] In 1827, he was named vicar general to Archbishop Francis Anthony de Méan of Mechelen,[2] and organized the opposition of the clergy to the religious policies of William I.

[4] Belgium became a separate ecclesiastical province with Mechelen as an archbishopric and the suffragan dioceses of Liège, Namur, Tournai, Bruges and Ghent.

Archbishop Sterckx took full advantage of the new freedoms to completely reorganize his Archdiocese, establishing schools, colleges, monasteries, charities and minor seminaries in Hoogstraten and Waver.

During the consistory of 13 September 1838, the Pope appointed him as a cardinal with the title of cardinal-priest of St. Bartholomew en l'Ile (San Bartolomeo all'Isola).

In 1842, Sterckx issued a decree regarding plainsong and the following year established a commission to prepare a new edition of choral books.

[9] Cardinal Sterckx died on 4 December 1867, in Mechelen, where his remains rest in the crypt of the archbishops in St. Rombout's Cathedral.