[2] Hohenhausen was born in Dachau, the son of Johann Nepomuk Freiherr von Hohenhausen (also called "Peregrinus") by his marriage to Maria Anna, Freiin von Wittorf.
He was a nephew of Major-General Sylvius Maximilian von Hohenhausen (born 1738).
[3] Leonhard von Hohenhausen served in the Bavarian army during the campaigns between 1805 and 1815.
After acting as war minister under Ludwig I of Bavaria from 1847 to 1848 he was advanced to Lieutenant General and became a divisional commander.
In 1861 he was appointed as "Generalkapitän", commanding officer of the Hartschiers' a Bavarian life guards troop.