Louis was born to Charlemagne and Hildegard of Vinzgau at Chasseneuil. The third surviving son, he was made King of Aquitaine as an infant, beginning his lifelong association with that region.

Pope Adrian I crowned the young Louis as King of Aquitaine in Rome. This early coronation established his legitimacy and prepared him for eventual greater responsibilities within Charlemagne's empire.

Louis began participating in military campaigns alongside his father. Though he proved a capable administrator, he was less enthusiastic about warfare than his brothers, preferring scholarship and religious devotion.

Louis married Ermengarde of Hesbaye, a noble Frankish woman. Their marriage produced three sons who would later struggle for the empire: Lothair, Pepin, and Louis the German.

Louis led a successful campaign that captured Barcelona from the Muslims. This victory established the Spanish March as a buffer zone and demonstrated his military competence.

With his older brothers deceased, Charlemagne crowned Louis as co-emperor at Aachen. This secured his succession to the imperial throne and ensured a peaceful transition of power.

Upon Charlemagne's death, Louis became sole ruler of the Carolingian Empire. He immediately began reforms to strengthen the church and impose moral standards on the clergy and laity.

Pope Stephen IV traveled to Reims to crown Louis, the first papal coronation of a Carolingian emperor on Frankish soil. This reinforced the alliance between empire and papacy.

Louis issued the Ordinatio Imperii, establishing Lothair as primary heir and assigning subordinate kingdoms to his other sons. This attempt to ensure unity would ironically fuel later civil wars.

Empress Ermengarde died, leaving Louis a widower with three sons. Her death would lead to his remarriage and the birth of a fourth son, complicating succession arrangements.

Louis married Judith of Bavaria, a beautiful and ambitious noblewoman. Their marriage produced Charles (later Charles the Bald), whose claims would disrupt the carefully planned succession.

Louis's sons rebelled, and his army deserted him at the Field of Lies near Colmar. He was deposed and forced to perform public penance, a profound humiliation for the emperor.

Louis was restored to power after his sons quarreled among themselves. Loyal supporters rallied to him, and he resumed his reign, though with diminished authority and prestige.

Louis assigned significant territories to his youngest son Charles, attempting to secure his inheritance. This decision angered his older sons and perpetuated family conflicts.

Louis's son Pepin died, altering succession dynamics. Louis attempted to transfer Aquitaine to Charles, but Pepin's sons contested this, adding to the empire's instability.

Louis made a final division of the empire between Lothair and Charles, effectively disinheriting Louis the German. This settlement satisfied no one and ensured future conflict.

Louis the German rebelled against his father's final settlement. The aged emperor gathered forces to suppress the rebellion but was worn down by decades of family strife.

Louis the Pious died at Ingelheim while campaigning against his rebellious son. His death triggered civil war among his sons, leading to the Treaty of Verdun and the permanent division of Charlemagne's empire.