Johann Sigismund Graf von Riesch (2 August 1750 – 2 November 1821) joined the army of Habsburg Austria as a cavalry officer and, during his career, fought against the Kingdom of Prussia, Ottoman Turkey, Revolutionary France, and Napoleon's French Empire.

During the 1805 Ulm Campaign in the Napoleonic Wars, the French badly defeated his corps and forced it to surrender soon afterward.

Born in Vienna on 2 August 1750 into a noble Saxon family, Riesch enlisted in the army of the Electorate of Saxony.

That year found him serving in the Army of the Upper Rhine under Dagobert Sigmund von Wurmser and later under Maximilian Anton Karl, Count Baillet de Latour.

[1] Riesch led a small cavalry division in Archduke Charles' success at the Battle of Würzburg on 3 September 1796.

Riesch and Ludwig Baillet de Latour led their commands against the French divisions of Michel Ney and Jean Hardÿ in the Battle of Ampfing on 1 December.

[6][7] Two days later, Riesch's 13,000-man Left Column advanced against Jean Moreau's French army in the Battle of Hohenlinden.

The 22,000-strong Left Center Column made rapid progress on the main highway while Riesch's men struggled along muddy forest trails in snowy weather.

[8] Riesch's men found themselves in a soldiers' battle amid woods and snow squalls, with the more aggressive French having the advantage.

Charles Decaen's French division soon appeared on the scene to block Riesch's awkward attempts to break through to Kollowrat.

In attempting to escape the trap, Mack sent Franz von Werneck's corps to the northeast of Ulm and ordered Riesch to cover his right flank.

[16] During the battle, Riesch commanded two brigades under Daniel Mécsery and Johann Laudon, with 14 infantry battalions, 11 cavalry squadrons, and 12 artillery pieces.

[17] The main French attack came from the south, as Louis Henri Loison's division crossed a partly destroyed bridge over the river and went on to storm the Elchingen Abbey.