He first saw active service under Prince Eugene of Savoy in the War of the Spanish Succession, and by 1716 had risen to the command of Prince Eugene's own regiment of dragoons. He distinguished himself greatly at the battles of Peterwardein and Belgrade, and became in 1723 major-general of cavalry (General-Wachtmeister), in 1726 proprietary colonel of a regiment and in 1733 lieutenant field marshal.
In 1734 the War of the Polish Succession brought him into the field again. He was present at the battle of Parma (29 June 1734), where Count Mercy, the Austrian commander, was killed, and after Mercy's death he held the chief command of the army in Italy till Field Marshal Königsegg's arrival. Under Königsegg he again distinguished himself at the battle of Guastalla (19 September 1734). He was once more in command during the operations which followed the battle, and his skilful generalship won for him the grade of general of cavalry. He continued in military and diplomatic employment in Italy to the close of the war.
In 1737 Khevenhüller was made field marshal, Prince Eugene recommending him to his sovereign as the best general in the service. His chief exploit in the Turkish War, which soon followed his promotion, was at the battle of Radojevatz (28 September 1737), where he cut his way through a greatly superior Turkish army.
Khevenhüller surpassed himself in the War of the Austrian Succession. As commander-in-chief of the army on the Danube he not only drove out the French and Bavarian invaders of Austria in a few days of rapid marching and sharp engagements (January 1742), but overran southern Bavaria, captured Munich, and forced a large French corps in Linz to surrender. Later in the summer of 1742, owing to the inadequate forces at his disposal, he had to evacuate his conquests, but in the following campaign, though now subordinated to Prince Charles of Lorraine, Khevenhüller reconquered southern Bavaria, and forced the emperor in June to conclude the unfavourable convention of Nieder-Schönfeld. He disapproved the advance beyond the Rhine which followed these successes, and the event justified his fears, for the Austrians had to fall back from the Rhine through Franconia and the Breisgau, Khevenhüller himself conducting the retreat with admirable skill.
On his return to Vienna, Maria Theresa decorated the field marshal with the order of the Golden Fleece. He died suddenly at Vienna on 26 January 1744.
Khevenhüller wrote various instructional works for officers and soldiers (Des G. F. M. Grafen von Khevenhüller Observationspunkte für sein Dragoner-Regiment (1734 and 1748) and a règlement for the infantry (1737)), and an important work on war in general, Kurzer Begriff aller militärischen Operationen (Vienna, 1756; French version, Maximes de guerre, Paris, 1771).
Original text from 1911encyclopedia.org