Vécsey became renowned for leading from the front. He became "Oberst" (Colonel) of the "Archduke Ferdinand" Hussar Regiment Nr. 3, which he led at the Battle of Caldiero on 29–31 October 1805 during the War of the Third Coalition. On 14 August 1808 he was promoted to "General-major". In 1809 during the War of the Fifth Coalition, he was given command of a brigade in the Austrian II Armeekorps, which was led by Feldzeugmeister Johann Kollowrat. His brigade included the 7th and 8th Jäger Battalions, the 2nd Battalion of the "Archduke Charles" Legion, the "Klenau" Chevauleger Regiment Nr. 5, and a brigade battery with eight 3-pound cannons. The division commander was Feldmarschallleutnant Johann von Klenau. At the beginning of the campaign, his brigade was detached from its army corps and served as an independent link between the I and II Armeekorps north of the Danube and the III, IV, V, VI, I Reserve, and II Reserve Armeekorps south of the river. The brigade operated on the south bank.