As archbishop, Vicari endeavoured to release the Church of Baden from the bonds of Josephinism and the principles of Wessenberg, and to defend its rights against the civil government.
To overcome prevalent religious indifference he emphasized the rights of bishops in training and appointing the clergy, and enforced discipline as regards mixed marriages.
In a violent dispute with the Government over his prohibition of a Requiem Mass for deceased Protestant rulers he was victorious, as also in later contests about the schools.
Though placed under police supervision and held prisoner in his palace, he brought about the reorganization of Catholic life in Baden.
In numerous pastoral letters and exercises, he animated the priests for their high calling, exhorted them to the fulfilment of their duties, and punished disobedience.