Mirabeau's life before 1789 was characterized by wild excesses, which ruined his health and caused him to be repeatedly jailed—several times on the request of his father, with whom he carried on a public quarrel. For a while he supported himself by writing. The year 1785 found him an exile in England, where he moved in Whig circles, but in 1786 he was sent on a secret mission to Prussia. He betrayed his government's trust by publishing his unedited reports to Paris, containing accounts of scandal and intrigue in the Prussian court. The author of numerous pamphlets in which he violently denounced various abuses of the ancien régime, he was elected (1789) a delegate of the third estate for Aix-en-Provence in the States-General. His clear and practical ideas, his fiery eloquence, and his terrifying yet imposing appearance exerted a fascination over the delegates and the populace.
Despite his unsavory personal reputation, he found himself the spokesman of the third estate, particularly when, on June 23, the king ordered the States-General to leave the hall after the day's session had been declared closed. To the marquis de Dreux-Brézé, who announced the king's order, Mirabeau replied (his words have been variously reported): "We shall not leave our places save by the force of bayonets." The assembly remained in session and adopted Mirabeau's motion that its members were inviolable. However, despite his sonorous phrases, Mirabeau from the very beginning of the French Revolution sought to create a strong constitutional monarchy on the British model, which would permit him to play a decisive role as prime minister. In the Constituent Assembly he endeavored to strengthen the king's constitutional powers. However, members of the Assembly were barred from cabinet posts by a decree (Nov., 1789) specifically directed against him.
Shortly afterward Mirabeau began secret dealings with the court. He entered the pay of the king and queen and, beginning in May, 1790, dispatched a series of advisory notes to them. The royal couple did not heed his counsel, for he never entirely gained the confidence of the court, particularly of the queen. Meanwhile, he was increasingly criticized in the assembly, particularly by the Jacobins, who opposed his moderation; his political position was becoming untenable. He died in Apr., 1791, amid impressive manifestations of public sorrow and respect, for he had never lost his popularity with the masses. He was buried in the Panthéon, but his body was later removed when his dealings with the court were discovered.
See L. de Loménie and C. de Loménie, Les Mirabeau (5 vol., 1879-81); F. M. Fling, Mirabeau and the French Revolution (1908); biographies by P. F. Willert (1898, repr. 1970); H. de Jouvenel (tr. 1929), P. Nezelov (tr. 1937), A. Vallentin (1948), and O. J. G. Welch (1951).