Joachim Murat was born 25 March 1767, in La Bastide, (renamed Labastide-Murat after its renowned citizen), in the Lot department of France, in the former province of Guyenne, to Pierre Murat-Jordy, an innkeeper, and his wife Jeanne Loubières, daughter of Pierre Loubières and of his wife Jeanne Viellescazes.

Murat enlisted in the cavalry at the age of twenty. In 1791, he joined the king's Constitutional Guard, but left it soon for the regular army. In 1792, he became an officer. He was a staunch supporter of the notorious revolutionary Jacobin Jean-Paul Marat, and thus believed in a philosophy championing a strong centralized government in the form of a republic.

In the autumn of 1795, three years after King Louis XVI of France was deposed, royalist and counter-revolutionaries organised an armed uprising. On 3 October, General Napoleon Bonaparte, who was stationed in Paris, was named commander of the French National Convention's defending forces. This constitutional convention, after a long period of emergency rule, was striving to establish a more stable and permanent government in the uncertain period after the Reign of Terror. Bonaparte tasked Murat with the gathering of artillery from a suburb outside the control of the government's forces. Murat managed to take the cannons of the Camp des Sablons and transport them to the centre of Paris while avoiding the rioters. The use of these cannons on 4 October allowed Bonaparte to save the members of the National Convention. For this success Joachim Murat was made chef de brigade (colonel) and thereafter remained one of Napoleon's best officers.

In 1796, with the situation in the capital and government apparently stabilised and the war going poorly, Napoleon lobbied to join the armies attempting to secure the revolution against the invading monarchist forces. Murat then went with Bonaparte to northern Italy, initially as his aide-de-camp, and was later named commander of the cavalry during the many campaigns against the Austrians and their allies. These forces were waging war on France and seeking to restore a monarchy in revolutionary France. His valour and his daring cavalry charges later earned him the rank of général in these important campaigns, the battles of which became famous as Bonaparte constantly used speed of maneuver to fend off and eventually defeat individually superior opposing armies closing in on the French forces from several directions. Thus, Murat's skills in no small part helped establish Bonaparte's legendary fame and enhance his popularity with the French people.

Murat commanded the cavalry of the French Egyptian expedition of 1798, again under Bonaparte. The expedition's strategic goal was to threaten Britain's rich holdings in India. (Some had been taken from France during the Seven Years' War). However, the overall effort ended prematurely because of lack of logistical support with the defeat of the French fleet due to British sea power. After the sea battle, Napoleon led his troops on land toward Europe (via Palestine and thence Ottoman Turkey), but was recalled by the Directory (at least in part) as it feared an invasion by Britain. Abbé Sieyès also saw Bonaparte as an ally against a resurgent Jacobin movement, and so the expeditionary army was turned over to a subordinate. The remaining non-military expedition staff officers, including Murat, and Bonaparte returned to France, eluding various British fleets in five frigates. A short while later, Murat played an important, even pivotal, role in Bonaparte's 'coup within a coup' of 18 Brumaire (9 November 1799) when Napoleon first assumed national power. Along with two others (including Director Abbé Sieyès), Napoleon Bonaparte set aside the five-man directory government, establishing the three-man French Consulate government.

Murat married Caroline Bonaparte in a civil ceremony on 20 January 1800 at Mortefontaine and religiously on 4 January 1802 in Paris, thus becoming a son-in-law of Letizia Ramolino as well as brother-in-law to Joseph Bonaparte, Napoleon I of France, Lucien Bonaparte, Elisa Bonaparte, Louis Bonaparte, Pauline Bonaparte and Jérôme Bonaparte.

Napoleon made Murat a Marshal of France on 18 May 1804, and also granted him the title of "First Horseman of Europe". He was created Prince of the Empire in 1805, appointed Grand Duke of Berg and Cleves on 15 March 1806 and held this title till 1 August 1808 when he was named King of Naples and Sicily.

Murat was equally useful in Napoleon's invasion of Russia (1812), and in the Battle of Leipzig (1813). However, after France's defeat at Leipzig, Murat reached an agreement with the Austrian Empire in order to save his own throne. During the Hundred Days, he realized that the European powers, meeting as the Congress of Vienna, had the intention to remove him and return the Kingdom of Naples and Sicily to its pre-Napoleonic rulers. Murat deserted his new allies, and, after issuing a proclamation to the Italian patriots in Rimini, moved north to fight against the Austrians in the Neapolitan War to strengthen his rule in Italy by military means. He was defeated by Frederick Bianchi, a general of Francis I of Austria, in the Battle of Tolentino (2-3 May 1815). He fled to Corsica after Napoleon's fall. During an attempt to regain Naples through an insurrection in Calabria, he was arrested by the forces of the legitimate King, Ferdinand IV of Naples, and was eventually executed by firing squad at the Castello di Pizzo, (Calabria).