Honoré IV was Prince of Monaco and Duke of Valentinois from 12 March 1795 to 16 February 1819. He was the son of Prince Honoré III by his wife, Maria Caterina Brignole, a Genoese noblewoman. After the fall of Napoleon I, he regained control of the principality thanks to a clause added by Charles Maurice de Talleyrand-Périgord at the Congress of Vienna stating that, "the Prince of Monaco should return to his estates", and passed on his titles to his eldest son, Honoré V, Prince of Monaco.
Honoré IV married Louise Félicité Victoire d'Aumont, Duchess of Aumont, Duchess Mazarin and of La Meilleraye on 15 July 1777 in Paris. They divorced in 1798. They had two sons: Honoré V, Prince of Monaco, and Florestan I, Prince of Monaco.
During the French occupation of Monaco, Honoré IV was imprisoned for several years. Illnesses resulting from this imprisonment incapacitated Honoré IV in his later years, and following the re-establishment of the Principality a regency was established to rule in Honoré's name. This regency was directed, first, by his brother Joseph Grimaldi, then from 1815 by his son, the Hereditary Prince Honoré who succeeded him in 1819 as Sovereign Prince Honoré V.