After a long and distinguished naval career, de Fayet became the seventh Governor-General of Saint-Domingue on 8 October 1732. He quickly became an acquaintance of Bastienne Josèphe, frequenting her brothel and occasionally supplying information to her secret intelligence network.
When the Assassin Adéwalé arrived in Port-au-Prince in 1735, de Fayet was attempting to use Bastienne as a go-between to negotiate a deal with Maroon resistance leader Augustin Dieufortto keep violence down, giving her a letter which outlined conditions for which they could sue for peace. Bastienne, in turn, directed Adéwalé to deliver the Governor's letter to Dieufort.
Adéwalé's arrival at the Maroon hideout was coincided by an ambush of Overseers, leading both men to suspect that the Governor was a "two-faced liar." Not long after this, de Fayet hosted a soirée with several guests from the French Geodesic Mission, including scientist and smuggler Louis Godin. It was here that Godin told de Fayet that the expedition would cost more than what they had initially calculated.
Although Pierre accused Godin of misappropriating funds, he agreed to lend additional support after Godin convinced him that the expedition would make it easier for him to import slaves. He also warned Godin not to offend his Spanish chaperons, as they needed Spain as an ally against the British Empire.
After the Experto Crede sunk a British Man O' War and liberated the Wellington plantation, de Fayet began dealing out harsher punishments to rebellious slaves, and issued strict military curfews every night. Abandoning all pretense of diplomacy, he told Bastienne that any act of violence by the Maroon resistance would be responded to in kind.
When Adéwalé and Augustin dismissed this warning, the French Navy scuttled a slave ship that the Maroons were about to liberate. Ultimately, this had the opposite effect of what de Fayet intended; instead of breaking the spirit of the rebels, it outraged them, and prompted Adéwalé to mark him for assassination.
After his troops captured a Maroon rebel, de Fayet brutally tortured the man for information on the location of the Maroon hideout, burning him with a branding iron when he refused to talk. It was at this moment that Adéwalé, who had infiltrated the Governor's mansion, fired his blunderbuss, killing five guards.
This prompted de Fayet to flee to a guard post, where he made a final stand accompanied by his best troops. Adéwalé's rage, coupled with his ferocious fighting style, enabled him to cut down the soldiers. De Fayet then proceeded to attack Adéwalé with the branding iron, but after being disarmed, he picked up a sword to defend himself, though Adéwalé was ultimately able to overpower him and kill him with his former weapon.
Though he appeared on the surface to be a stuffy diplomat, de Fayet was a sadistic man who viewed his slaves as little more than animals, referring to them as "beasts" during everyday conversation. In his final words to Adéwalé, he showed no remorse for the way he treated his slaves, insisting that they were animals who, without guidance from their masters, would resort to murder and rebellion. Infuriated by his words, Adéwalé said that in his case, he wished that were true.