The first member of the House of Capet to make a lasting contribution to the centralising institutions of royal power, Louis was born in Paris, the son of Philip I and his first wife, Bertha of Holland. Almost all of his twenty-nine year reign was spent fighting either the "robber barons" who plagued Paris or the Norman kings of England for their continental possession of Normandy. Nonetheless, Louis VI managed to reinforce his power considerably and became one of the first strong kings of France since the division of the Carolingian Empire. His biography by his constant advisor Abbot Suger of Saint Denis renders him a fully rounded character to the historian, unlike most of his predecessors.

In his youth, Louis fought the Duke of Normandy, Robert Curthose, and the lords of the royal demesne, the Île de France. He became close to Suger, who became his adviser. He succeeded his father on Philip's death on 29 July 1108. Louis's half - brother prevented him from reaching Rheims and so he was crowned on 3 August in the cathedral of Orléans by Daimbert, Archbishop of Sens. The archbishop of Reims, Ralph the Green, sent envoys to challenge the validity of the coronation and anointing, but to no avail.

On Palm Sunday 1115, Louis was present in Amiens to support the bishop and inhabitants of the city in their conflict with Enguerrand I of Coucy, one of his vassals, who refused to recognise the granting of a charter of communal privileges. Louis came with an army to help the citizens to besiege Castillon (the fortress dominating the city, from which Enguerrand was making punitive expeditions). At the siege, the king took an arrow to his hauberk, but the castle, considered impregnable, fell after two years.

Just before his death in 1137, William X, Duke of Aquitaine appointed Louis guardian of his daughter and heir, the young Eleanor of Aquitaine, and expressed his wish for her to marry Louis' son. The prospect of adding the Aquitaine to his son's domains made him so happy he could hardly speak.

Louis VI died on 1 August 1137, at the castle of Béthisy - Saint - Pierre, nearby Senlis and Compiègne, of dysentery. He was interred in Saint Denis Basilica. He was succeeded on the throne by his son Louis VII, called "the Younger," who had originally wanted to be a monk.

He married in 1104: 1) Lucienne de Rochefort — the marriage was annulled on 23 May 1107 at the Council of Troyes by Pope Paschal II. He married in 1115: 2) Adélaide de Maurienne (1092–1154). With Marie de Breuillet, daughter of Renaud de Breuillet de Dourdan, Louis VI was the father of a daughter.