From 1800 to 1817 he served in the Karl von Lothringen Regiment, a hussar unit in the Austrian Imperial Army.

He lived with his personal bodyguard or leibjäger in the Orangery, a modest lodge adjoining Bad Homburg Castle, where he devoted himself to his two main hobbies, hunting and the Romano-German era of the Taunus.

However, his lack of any male relations or issue made it clear that he would be the last landgraf of Hesse-Homburg even before his accession – his only younger brother, Leopold, had been killed in 1813.

He also re-confirmed the constitution accepted by Gustav, though he revoked it on 20 April 1852 at the end of the German National Parliament and reinstated authoritarian personal rule until his death.

He died without issue in Bad Homburg in 1866 – his remains filled the last space in the vault at Bad Homburg Castle and Hesse-Homburg was briefly inherited by Louis III, Grand Duke of Hesse, before being annexed by Prussia later in 1866 after the Austro-Prussian War.