In 1824 he visited the United States, to promote the emigration of free Blacks to Haiti.
At his return, in 1825, he established a private school, which will become known as the Granville Institute, before being asked to lead the National Lycee in Port-au-Prince.
He is considered to be the intellectual father of the 1843 Revolution that finally dislodged Jean-Pierre Boyer's authoritarian regime.
Granville was regarded as well-educated and refined, a man of knowledge and virtue.
He made popular in the U.S.
the Persian saying, "I write insults on sand and favours on marble."