In the summer of that year his father was dismissed from the army for refusing to execute the government's decrees directed against religious congregations, and retired to farm his family's land in Normandy.

[1] In 1925 Le Roy Ladurie settled in an 18th-century château surrounded by a farm of 140 hectares (350 acres) owned by his maternal family at Les Moutiers-en-Cinglais.

He was called a revolutionary for demanding review of tenancy leases and a reactionary for opposing the extension of social insurance to agriculture.

[8] Le Roy Ladurie was the General Secretary of the Front paysan that supported Henry Dorgères and his quasi-fascist Greenshirts in 1933–35.

[9] He published an article that violently attacked the government for lowering production targets at a time when there were 300,000 foreigners in France, many working "stolen" French soil and refusing to be assimilated.

[12] In June 1938 Le Roy Ladurie and his ally Alain de Chantérac were arrested for leading a peasant rally in Castres.

[1] At the outbreak of World War II in September 1939 Le Roy Ladurie tried to enlist with the 36th infantry regiment in Caen but was refused due to his poor health and to being the father of four young children.

Marshal Philippe Pétain, who had been a classmate of his father in war college, read the report at once and became friendly with Le Roy Ladurie.

[4] In December 1940 Pétain offered Le Roy Ladurie the Ministry of Agriculture in the new government being formed by Pierre-Étienne Flandin.

He refused because the position did not include authority for Supplies, which he saw as inextricably linked, and because he distrusted the extreme collaborationist faction led by Henri Martin.

[1] Increasingly hostile to the collaborationist regime, Le Roy Ladurie joined the Organisation civile et militaire of the French Resistance under the command of Maxime Blocq-Mascart.

The charges were dismissed six months later by the High Court of Justice in view of his resistance activity, but his participation in Vichy handicapped his future political career.

He was elected deputy in 1951 under the label of the Union of Independent and Republican Nationals,[18][19] a group that campaigned for amnesty for participants in the Vichy regime.