Born in Cospicua in 1933, Mifsud Bonnici was the seventeenth prime minister of Malta (1984-87).
He received his education at the Lyceum and the RUM from where he graduated BA (1950) and LI,.D. (1954). He furthered his studies on taxation and industrial law at University College, London (1967-68).
During his student years, Mifsud Bonnici was active in the Catholic Social Guild and the Young Christian Workers and he was also a member of the editorial board and legal advisor of its newspaper, Il-Haddiem. In 1969 he was appointed lecturer in industrial and fiscal law at the RUM and chosen as legal consultant of the GWU. In this capacity, he strongly criticized the enactment of the proposed Industrial Relations Bill.
On 29 May 1980 Prime Minister Dom Mintoff proposed Mifsud Bonnici as deputy leader of the MLP responsible for party affairs. On 15 October 1982, on a motion put forward by Mintoff himself, the party’s general conference appointed Mifsud Bonnici designate leader.
Mifsud Bonnici was co-opted to parliament on 2 May 1982 and given the portfolio of minister of labour and social services, a position he held up to September 1983, when he was appointed senior deputy prime minister and minister of education and culture. During this time he was the leading speaker and negotiator in the Church-State dispute on the introduction of free education for all.
On 22 December 1984 Mintoff resigned and Mifsud Bonnici was sworn in as the new prime minister and MLP leader. His responsibilities also included the ministry of interior and the ministry of education. In May 1987 he successfully contested the general elections on two electoral districts but the MLP lost power and Mifsud Bonnici was sworn in as leader of the opposition. He was confirmed leader of the MLP in 1992, but resigned from party leader soon afterwards. He did not contest the 1996 elections. In 1990 Mifsud Bonnici was nominated Companion of Honour of the National Order of Merit (KUOM).