Louis, as he was usually called, was educated together with his elder brother Frederick VI. They studied together in Geneva, and in 1788, they joined the Prussian army together. In 1793, he fought in the Battle of Pirmasens. In 1798, he was promoted to major. In 1804, he was promoted to lieutenant colonel and he married Princess Augusta Amalia of Nassau-Usingen, daughter of Frederick Augustus, Duke of Nassau. This "dynastic marriage" with the daughter of a neighbouring prince was an unhappy one, as she was in love with Count Frederick William of Bismarck. The marriage ended in divorce. Augusta Amalia married Frederick William; Louis William did not marry again. Ricarda Huch gives more details in her "Count Mark and the Princes of Nassau-Usingen. A tragic biography" of 1925.