Delgrès was born free in Saint-Pierre, Martinique. An experienced military officer who had a long background fighting Great Britain in the many wars that country had with Revolutionary France, Delgrès took over the resistance movement from Magloire Pélage after it became evident that Pélage was loyal to Napoleon. Delgrès believed that the "tyrant" Napoleon had betrayed both the ideals of the Republic and the interests of France's colored citizens, and intended to fight to the death. The Jacobin government had granted the slaves their freedom, in Guadeloupe and other French colonies, but Napoleon attempted to reinstate slavery throughout the French Empire in 1802.
The French army led by Richepanse drove Delgrès into Fort Saint Charles, which was held by the slaves. After realizing that they could not overcome the French forces and refusing to surrender, Delgrès left with 400 men and some women. At the Battle of Matouba on May 28, 1802, Delgrès and his followers ignited their gunpowder stores, committing suicide in the process, in an attempt to kill as many of the French troops as possible.
In April 1998, Delgrès was officially admitted to the French Panthéon, although the actual location of his remains is unknown. Delgrès' memorial is opposite that of Toussaint Louverture, leader of the Haitian Revolution, the location of whose remains is also a mystery.