Louis was born at Philippsthal as the son of William, Landgrave of Hesse-Philippsthal and his wife, Princess Ulrike Eleonora of Hesse-Philippsthal-Barchfeld.

A prince of the family of the Landgraves of Hesse-Philippsthal, he fought for the Kingdom of Naples during the Napoleonic Wars.

In the course of the War of the Third Coalition, he commanded the garrison of the fortress of Gaeta in the siege laid by the French in 1806, refusing to obey the order of the Neapolitan government to surrender it.

After the death of his brother Charles in the siege of Frankfurt in 1793, Louis succeeded him as hereditary prince of the landgraviate of Hesse-Philippsthal.

Marie Franziska had connections, and obtained a position for her husband in the army of the Kingdom of Naples, as she served as the Mistress of the Robes at the court of Queen Maria Carolina.