As a professor, he taught at the University of Toliara during the 1980s and was Director of Personnel and Human Resources at the Autonomous Port of Toamasina from 1987 to 1989.
He served as a Deputy until the National People's Assembly was dissolved and transitional institutions were established in 1991.
[2] During the 2009 political crisis, the four main political factions reached an agreement on 6 October 2009 that provided for Andry Rajoelina to remain in his position as Transitional President while also designating Mangalaza to replace Rajoelina ally Monja Roindefo as Prime Minister.
[3] At the time, Mangalaza was viewed as a politically obscure figure, and his selection was considered surprising.
[6] Roindefo took the matter to the Council of State on 12 October 2009, requesting that it annul the decree appointing Mangalaza; he argued that the procedure was flawed and that the faction leaders needed to sign the agreement in order for it to become valid.