He was instrumental in the reorganization of the military music system in the Austrian Empire.
After his musical education in Eger, he entered the band of the infantry regiment "Kaiser Alexander" in Vienna in 1818.
There he also took lessons with Niccolò Antonio Zingarelli, director of the Conservatory and conductor at the Naples Cathedral.
With the 27th Infantry Regiment, he returned to Graz in 1835, where he left the army and took over as the director of the music association for Styria.
His son was Gustav von Leonhardt [de] (1838–1891), Secretary General of Austria's central bank Oesterreichische Nationalbank.