Louis received his education at the court of Duke Christoph of Württemberg.

He had the Marburg Castle renovated by his architect Ebert Baldewein.

Wanting to enlarge his territory peacefully, he bought parts of the Fuldischen Mark in 1570 from the counts of Nassau-Saarbrücken and the rest in 1583 from the count of Nassau-Weilburg.

On 10 May 1563 he married Hedwig of Württemberg and his second marriage was to Marie, Countess of Mansfeld.

His 1597 will bequeathed his territory between his nephew, Maurice of Hesse-Kassel and Louis V of Hesse-Darmstadt, on the condition that it would remain Lutheran.