Born in the Hôtel des Deux-Ponts in Strasbourg, he was the son of Count Palatine Maximilian Joseph of Zweibrücken (later Maximilian I Joseph of Bavaria) by his first wife Princess Augusta Wilhelmine of Hesse-Darmstadt. At the time of his birth, his father was an officer in the French army stationed at Strasbourg. He was the godson and namesake of Louis XVI of France.
On 1 April 1795 his father succeeded Ludwig's uncle, Charles II, as duke of Zweibrücken, and on 16 February 1799 became Elector of Bavaria and Count Palatine of the Rhine, the Arch-Steward of the Empire, and Duke of Berg on the extinction of the Sulzbach line with the death of the elector Charles Theodore. His father assumed the title of King of Bavaria on 1 January 1806.
Starting in 1803 Ludwig studied in Landshut where he was taught by Johann Michael Sailer and in Göttingen. On 12 October 1810 he married Therese of Saxe-Hildburghausen (1792–1854), the daughter of Frederick, Duke of Saxe-Hildburghausen. The wedding was the occasion of the first-ever Oktoberfest.
Ludwig strongly rejected the alliance of his father with Napoleon I of France but in spite of his anti-French politics the crown prince had to join the emperor's wars with allied Bavarian troops in 1806. As commander of the 1st Bavarian Division in VII Corps, he served under Marshal François Joseph Lefebvre in 1809. He led his division in action at the Battle of Abensberg on 20 April.
With the Treaty of Ried of 8 October 1813 Bavaria left the Confederation of the Rhine and agreed to join the Sixth Coalition against Napoleon in exchange for a guarantee of her continued sovereign and independent status. On 14 October, Bavaria made a formal declaration of war against Napoleonic France. The treaty was passionately backed by Crown Prince Ludwig and by Marshal von Wrede.
Already at the 1815 Congress of Vienna, Ludwig advocated a German national policy. Until 1816 the crown prince served as governor-general of the Duchy of Salzburg, which cession to Austria he strongly opposed. His second son Otto, the later King of Greece, was born there. Between 1816 and 1825, he spent his years in Würzburg. He also made numerous trips to Italy and stayed often in the Villa Malta in Rome, which he later also bought (1827). Ludwig supported generously as a Philhellene the Greek War of Independence, in which he in the war of 1821 provided a loan of 1.5 million florins from his private funds.
In 1817 Ludwig was also involved in the fall of Prime Minister Count Max Josef von Montgelas whose policies he had opposed. He succeeded his father on the throne in 1825.