After completing his primary and secondary schooling at Institution Saint-Louis de Gonzague, Dominique began studying at the Faculté d’Agronomie at in 1948, where he received his degree in 1951. Dominique then received a scholarship to studied genetically modified cacao and coffee plants at the in Paris. He returned to Haiti in 1955 leaving his girlfriend while she is pregnant and began to work as an agronomist in in the Nord department with the Institut Haïtien de Crédit Agricole et Industriel as well as the Société Haitiano-Américaine de Développement Agricole (SHADA), primarily on sisal and rubber production. He worked alongside agronomist Edner Vil, who was subsequently arrested and killed by the Duvalier regime for promoting the rights of peasant farmers. Dominique, who had been working with the ti peyizan to defend their land rights against the chefs de section (local Duvalierist authorities) and wealthy landowners, was arrested a few weeks after his brother's attempt to overthrow the regime, and he spent six months in prison in Gonaïves. After his release, he was no longer permitted to work as an agronomist, and instead became a journalist.