Tellier's father married him to an heiress, the marquise de Courtenvaux, and instructed him in the management of state business. The young man won the king's confidence, and in 1666 he succeeded his father as war minister. His talents were perceived by Turenne in the war of Devolution (1667-68), who gave him instruction in the art of providing armies. After the peace of Aix-la-Chapelle, Louvois devoted himself to organizing the French army. The years between 1668 and 1672, says Camille Rousset, "were years of preparation, when Lionne was labouring with all his might to find allies, Colbert to find money, and Louvois soldiers for Louis."
The work of Louvois in these years is bound up with the historical development of the French army and of armies in general. Here need only be mentioned Louvois's reorganization of the military orders of merit, his foundation of the Hotel des Invalides, and the almost forcible enrolment of the nobility and gentry of France, in which Louvois carried out part of Louis's measures for curbing the spirit of independence by service in the army or at court. The success of his measures is to be seen in the victories of the great war of 1672-78. After the peace of Nijmegen Louvois was high in favour, his father had been made chancellor, and the influence of Colbert was waning. The ten years of peace between 1678 and 1688 were distinguished in French history by the rise of Madame de Maintenon, the capture of Strassburg and the revocation of the Edict of Nantes, in all of which Louvois bore a prominent part. The surprise of Strassburg in 1631 in time of peace was not only planned but executed by Louvois and Monclar. A saving clause in the revocation of the Edict of Nantes, which provided for some liberty of conscience, if not of worship, Louvois sharply annulled with the phrase "Sa majesté veut qu'on fasse sentir les dernières rigueurs a ceux qui ne voudront pas se faire de sa religion."
He claimed also the credit of inventing the dragonnades, and mitigated the rigour of the soldiery only in so far as the licence accorded was prejudicial to discipline. Discipline, indeed, and complete subjection to the royal authority was the political faith of Louvois. Colbert died in 1683, and had been replaced by Le Pelletier, an adherent of Louvois, in the controller-generalship of finances, and by Louvois himself in his ministry for public buildings, which he took that he might be the minister able to gratify the king's two favourite pastimes, war and building. Louvois was able to superintend the successes of the first years of the war of the League of Augsburg, but died suddenly of apoplexy after leaving the king's cabinet on July 16, 1691. His sudden death caused a suspicion of poison.
Louvois was one of the greatest of the rare class of great war ministers. French history can only point to Carnot as his equal. Both had to organize armies out of old material on a new system, both were admirable contrivers of campaigns, and both devoted themselves to the material well-being of the soldiers. In private life and in the means employed for gaining his ends, Louvois was unscrupulous and shameless.
The principal authority for Louvois's life and times is Camille Rousset's Histoire de Louvois (Paris, 1872), a great work founded on the 900 volumes of his despatches at the Depôt de la Guerre. Saint Simon from his class prejudices is hardly to be trusted, but Madame de Sévigné throws many side-lights on his times. Testament politiquede Louvois (1695) is spurious.