Born in Nymphenburg palace, near Munich, he was the son of Maximilian II of Bavaria and Princess Marie of Prussia. Ludwig ascended to the Bavarian throne at age 18 following his father's death. He was by all accounts strange to begin with, and as his rule progressed, he became even more antisocial and withdrew into seclusion in the Alps most of the time, where he built several expensive fairytale castles. The most famous, Neue Burg Hohenschwangau (now known as Neuschwanstein), was not completed until years after his death, and is now a popular tourist attraction.
Ludwig was engaged to Princess Sophie of Bavaria who was his cousin and sister of Elisabeth of Austria ("Sissi"). Their engagement was publicized on January 22, 1867, but after after having repeatedly postponed the wedding date, he finally canceled it in October. Sophie later married Ferdinand Philippe Marie, duc d'Alenšon (1844-1910), son of Louis Charles Philippe Raphael, duc de Nemours.
Mystery surrounds his death by drowning in Lake Starnberg in Berg, south of Munich. A little chapel was later built near the site of his drowning. A remembrance ceremony is held there each year on the day of his death.