His family was expelled by the Germans and took refuge in Marseille, where Joseph Thierry began to study Law.

[1] In 1903 Thierry was among a group of right-wing members of the Progressistes who formed the new Fédération républicaine (FR), a party of the center-right.

[2] Other founders included liberal opponents of the second empire and dedicated republicans such as Alexandre Ribot, Jules Méline, Henri Barboux and Édouard Aynard.

[4] Thierry initiated annual party conferences, and managed to increase support for the FR in the provinces.

[5] In November 1910 he asked his party to accept the lay laws that Aristide Briand proposed under his "appeasement" policy.

[7] As rapporteur for the standing parliamentary commission on customs, in 1910 Thierry represented the views of the reformist Fédération Intercolonial to an inter-ministry committee that had been set up "to fix the basis for the establishment of a colonial customs regime more favorable to the economic development of our colonies."

[1] On 7 May 1916 Thierry assisted Marcel Sembat, Minister of Public Works, in inaugurating the Rove Tunnel and the first two cranes of Port-de-Bouc.

"[14] He was Minister of Finance at a time when the offensive of General Robert Nivelle had failed and the war seemed to be in a stalemate.

[15] Thierry accompanied Étienne Clémentel, Minister of Commerce, to the London Conference, where France negotiated an easing of prohibitions on foreign trade in the agreement of 6 July 1917.

Thierry was named in the law of 31 July 1917, which continued the fiscal reform that was caused by the introduction of income tax.

In addition, he introduced taxes on income from business (4.5%), agriculture (3.75%), employment (3.75%), professional fees (3.75%) and revenue from capital (4%).