Dessalines was born as a slave in Grande-Rivière-du-Nord in what was at that time the French colony of Saint-Domingue on the island of Hispañola. He first served as an officer in the French army and later rose to become a commander in the revolt against the same colonial power. After the capture of Toussaint L'Ouverture in 1801, Dessalines became leader of the revolution and, after defeating the French troops sent by Napoleon in November 1803, he declared Haiti independent on January 1, 1804, in Gonaïves. He assumed the office of Governor General, but then he declared himself emperor of Haiti in 1805.
Dessalines was trying to keep the sugar industry and plantations running and producing without slavery. The colored people and the black people both fought against this system that he was bestowing upon them.
During his reign, Haiti became a nation of two castes. The mainly black peasants resided on the countryside producing their own food and working their own land, while in the towns the richer people, who were generally lighter skinned, had dominated both commerce and politics. Even though a majority of whites left the island, racial conflicts still arose among the blacks and colored. Dessalines, who had been born as a slave, held a grudge against both whites and light-skinned people. Once in power he demanded that all of the remaining French whites be massacred.
Dessalines declared Haiti an all black nation and forbade whites from ever again owning property or land there. Dessalines took over lands and property that held any value by any means necessary, including force and murder. His goal was to centralize most if not all of the productive plantations in the hands of himself, the state, and his cronies.
He also enforced a harsh regimen of plantation labour, described as caporalisme agraire (agrarian militarism) by the historian Michel-Rolph Trouillot. Dessalines demanded that all blacks either work as soldiers of his army or laborers in the plantations or fields.
Dessalines also believed in the tight regulation of foreign trade, which however was essential for Haiti's sugar- and coffee-based export economy. Dessalines favoured merchants from Britain and the United States over those from France.
For his administration, Dessalines needed literate and educated officials and managers; Dessalines placed in these positions well-educated Haitians, who were disproportionately from the light-skinned elite. As his system began to emerge, many blacks fled into the hills to get away from it.
A conspiracy to overthrow him involved both Henri Christophe and Alexandre Pétion, who succeeded him. The Emperor was assassinated near Port-au-Prince on October 17, 1806 on his way to fight the rebels.