He was born on Feb. 15, 1710, in the Palace of Versailles. His father was the grandson of the reigning monarch, King Louis XIV. That king had reigned for nearly 70 years by this time, his oldest son and oldest grandson (all named Louis) were still alive, and an orderly and hereditary succession seemed extremely likely. All of that changed within the space of two years, however. The Dauphin, the heir-in-waiting, died of smallpox in 1711; the following year, the Dauphin's oldest son also died. He left behind two sons, both named Louis. The older died not long after his father. Thus, at age 2, the very young Louis was suddenly heir to the throne.

King Louis XIV died in 1715, and the 5-year-old great-grandson became King Louis XV. The normal practice was for a young king's mother to serve as regent. Louis's mother predeceased her husband, and so Louis had no straightforward regent on which to depend for running the government until he came of age. The next nearest relative was Philippe II, a nephew of Louis XIV. The king, before he died, had specified that he preferred a regency council for his young son and successor. Philippe II took matters into his own hands and convinced the Parlement to annul Louis's will and give him the regency; in exchange, the leaders of Parlement made Philippe II recognize that they had the right to challenge the king's decision.

Young Louis grew up at the Tuileries Palace, learning the rules and responsibilities of being a king. He studied geography and science and learned to hunt and to ride horses. One of his tutors was André-Hercule de Fleury.

He was crowned king in October 1722, and the regency ended a few months later. Not long afterward, the king began to focus on gaining a wife. He and his first minister, the Duke of Bourbon, chose a Polish princess named Marie Leszcyńska. The couple were married in 1725, when he was 15 and she was 22. They had 10 children together during the next decade. Despite the presence of a loving wife and a large family, Louis began to spend more time with other women. One of the most famous of his favorites was Madame de Pompadour. A later favorite was Madame Du Barry.

Famous writers and thinkers like Diderot, Montesquieu, Rousseau, and Voltaire were alive and thriving during the reign of Louis XV. They were major figures in the Age of Enlightenment, an intellectual movement that spread throughout Europe in the 18th Century.

The king also enjoyed architecture and oversaw the building of the Ecole Militaire, the Place de la Concorde, the Petit Rianon, and what is now the Pantheon.