The Diocese of Mangochi, part of the ecclesiastical province of Blantyre, was first established on 29 May 1969 as the Apostolic Prefecture of Fort Johnston, taken from the Diocese of Zomba. It was promoted to a diocese on 17 September 1973.
Since its founding, the Diocese has been led by Bishop Alessandro Assolari (1973–2004), Bishop Luciano Nervi (2004–2005), Bishop Alessandro Pagani (2007–2013), and Bishop Monfort Stima (2013–present). Over the years, it has grown in faith, pastoral care, and social outreach, serving the Catholic community across Mangochi.