Following the assassination of President Jovenel Moïse on 7 July 2021,[4] Joseph led the Council of Ministers, which exercises executive power during a presidential vacancy.

[6] On 19 July 2021, it was announced that Joseph would yield the prime ministership to Henry and remain the Minister of Foreign Affairs and Worship.

[9] Joseph holds a doctorate in public policy from The New School in New York City where he was awarded a full merit-based scholarship as well as the Isador Lubin Fellowship, and worked as a university professor in the United States.

Joseph assumed political control of the government,[5] and blamed the attack on "a group of unidentified individuals, some of whom spoke in Spanish and English.

[22] On 19 July, Joseph announced in an interview with The Washington Post that he would be stepping down soon and handing over power to Henry, whom he had met with many times in the past week to resolve the dispute, but expected that he will remain the foreign minister in that government.

[26] On 3 September 2022, Joseph launched his own political party named Les Engagés pour le Développement ("Committed to Development").