During the War of the Spanish Succession, he went to Spain, where he was the Chief Intendant and Prime Minister of the Archduke Karl, who became Emperor Charles VI after the sudden death of his brother in 1711.

He was the Obersthofmeister (Imperial Chief Intendant) and Chairman of the Secret Council until he died in 1721.

This was done so that Anton Florian could be admitted to the Reichstag, which required that all members had land that was subordinate only to the Emperor himself (as opposed to land held in fief by higher nobles).

Anton Florian was the 591st Knight of the Order of the Golden Fleece in Austria.

Anton Florian married Countess Eleonore Barbara Catharina von Thun und Hohenstein (4 May 1661 – 10 February 1723) on 15 October 1679.