After serving as Governor of the Bank of Central African States (BEAC) from 1978 to 1990, Oyé-Mba was Prime Minister of Gabon from 3 May 1990 to 2 November 1994.

A member of the Fang ethnic group,[2] Casimir Oyé-Mba was born in Nzamaligué, located in the Komo-Mondah Department of Estuaire Province.

Next, he obtained a Diploma of Specialized Studies (DESS) at the Faculty of Law of Paris, and defended his doctorate thesis at the same institution in 1969.

[3] Oyé-Mba was an unsuccessful candidate for the position of President of the African Development Bank in 2005; he reached the fourth round of voting on the first day of the election, 18 May 2005.

[17] The Patriotic United Forces (FPU), an opposition group, announced on 29 July 2009 that it was supporting Oyé-Mba's candidacy.

[18] Speaking in Libreville on 9 August, Oyé-Mba said that he would focus on fighting youth unemployment if he was elected and he said that "if young people no longer trust politicians, it is because of a sense that they have often been betrayed".

[20] During his campaign, which stressed his long experience, Oyé-Mba also called for more road construction (100 kilometers per year), saving money by reducing the number of ministers in the government, and reinstating the two-term limit on the Presidency.

[29] Oyé-Mba publicly cautioned against hastily dismantling the CFA franc, arguing that the currency union had helped its member countries control inflation.

[33] Ali Bongo Ondimba and Jean Ping posted tributes to Oyé-Mba on their Facebook pages.