Henry has been sheltering in Puerto Rico, unable to return home while receiving threats from the armed G9 Family gang and their leader Jimmy Cherizier, aka "Barbecue," who orchestrated organized attacks around Port-Au-Prince 2 weeks ago.
READ: Haitian capital under siege by gang headed by leader 'Barbecue' amid societal breakdown
Henry asked Haiti's citizens to remain calm in a video address, translated by BBC News, announcing his resignation.
"The government that I am leading will resign immediately after the installation of [a transition] council," Henry said.
"I want to thank the Haitian people for the opportunity I had been granted. I'm asking all Haitians to remain calm and do everything they can for peace and stability to come back as fast as possible."
Henry had been facing calls to resign since February after retracting his pledge to step down as prime minister, saying that the security of Haiti needed to be re-established to ensure fair elections by 2025.
He took over interim leadership of the country in July 2021 after former President Jovenel Moise's assassination, drawing questions and criticism from Haitians wondering why he would govern the country for so long without an elected president.
He failed to deliver on his promise of combating the gangs that controlled most of the slums and streets of the Haitian capital. During the organized attack, over 4,000 inmates were broken out of 2 of the country's largest prisons and have remained in the streets wreaking havoc.
READ: Haiti in state of emergency after thousands of violent criminals escape prison
A month-long state of emergency, as well as a curfew, was subsequently ordered, as Henry was in Kenya to officiate a deal to receive an international security force to help quell ongoing violence.
A former elections minister in Haiti, Mattias Pierre, called the situation "very precarious."
"The police force is weak, and more than 40 police stations [are] destroyed. The army is very limited and not equipped; gang members occupy most of the [Port-au-Prince] downtown and some government headquarters.
"Very soon people will be out of food, medication and... medical support."
He revealed that the gangs involved in the attacks want to be part of any new power-sharing deal as he stressed the importance of the "support" of an international armed force.