Duval was born in Rose Hill on 9 October 1930 in an upper middle-class Creole family of mixed ancestry.

At the January 1960 by-elections Gaëtan Duval was elected to the Legislative Council after promoting ethnic hatred and racial division during his electoral campaign.

By 1965 Koenig retired from politics and Duval became the leader of the PMSD which was a conservative movement backed by wealthy white Franco-Mauritian oligarchs as well as most of the creole community of Roman Catholic faith.

[5][6] For a few years in the 1950s Duval's party even received the support of the Muslims but this ended when Abdool Razack Mohamed left the PMSD to form the new CAM in 1959.

However his PMSD gradually split into rival factions, the main one being the Union Démocratique Mauricienne (UDM) formed by Guy Ollivry & Maurice Lesage within the Opposition in Parliament.

He made an electoral arrangement with then prime minister Jugnauth in the 1983 general elections and later joined the government, the alliance having been victorious.

His son, Xavier-Luc revealed to the population that he was ashamed of bearing the surname of Duval, due to the immoral lifestyle of his father.

[18][19] In 1989 two ex-prisoners Paul Sarah and Moorgesh Shummoogum alleged in a statement to the police that in 1971 Sir Gaetan Duval had planned and commandeered the murder of Azor Adelaide at his Grand-Gaube bungalow.

Paul Sarah, Moorgesh Shummoogum, Ignace Bahloo and André Celestin had already served prison sentences for their involvement in the 1971 murder.

[20] During the afternoon of 23 June 1989 Sir Gaetan Duval landed at Plaisance Airport in Mauritius from Madagascar and he was questioned by Superintendent of Police Reesaul of the Anti Drug and Smuggling Unit (ADSU).

[22] In recognition of his political and judicial career, France elevated him to the rank of Commandeur de la Légion d'Honneur in 1973.

[24] Several books have been written about Gaëtan Duval including 'Le droit à l’excès' and 'L’incarné du voyage' by Alain Gordon-Gentil.

In 2015 the documentary "Gaëtan Duval, Une Vie" was released by La Compagnie Des Autres in Mauritius.