Lothar Joseph Dominik Graf von Königsegg-Rothenfels (17 May 1673 – Vienna 8 December 1751) was an imperial Fieldmarshal.
Lothar was the youngest son of Count Leopold Wilhelm von Königsegg-Rothenfels and Maria Polyxena, Countess Scherffenberg. His parents sent him to the Jesuit school in Besançon, to become a priest. At the age of 16 Lothar became capitular in Salzburg and Passau. Then he was sent to Rome to finish his education.
But Lothar didn't want to become a priest, left Rome and joined the Imperial army which was fighting the Turks in Hungary at that time.
He served between 1691 and 1699 in the Cuirassier-Regiment "Hohenzollern" in the war against the Turks. Two years later he participated in the Italian campaign under Prince Eugene of Savoy in the War of Spanish Succession (1701–1714).
On 5 October 1702 he became a Colonel, and received command of his own Infantry regiment. Later he was promoted to Generalfeldwachtmeister and Feldmarschallleutnant.
He distinguished himself in the Battle of Turin (1706) and received command of the fortification of Mantua.
At the end of the war, Lothar played an important role in the negotiations for the Treaty of Rastatt.
Königsegg became commander of the Austrian troops of the newly conquered Habsburg Netherlands, between 1714 and 1717.
Between 1718 and 1722 he served as a diplomat in Paris and Warschau. In 1722 Königsegg became commander in Siebenbürgen, and became Fieldmarshal on 16 October 1723. After that he was a diplomat in The Hague and Madrid.
In 1731 he became a Knight in the Order of the Golden Fleece.