Montero's first incursion in politics was in 1931, when President Carlos Ibáñez del Campo named him Minister of the Interior and Social Welfare.

Supported by the Liberals and Conservatives as well as the Radicals, Juan Esteban Montero was the clear winner of the presidential elections, obtaining almost 64% of the popular vote, defeating leftist José Santos Salas, a protégé of former President Carlos Ibáñez.

Notwithstanding these harsh measures, the depreciation of the currency continued, and inflation soared while the Central Bank reserves were at an all-time low.

On June 4, 1932, colonel Marmaduke Grove staged a coup d'état by taking over the Air Force base of El Bosque, in Santiago, and demanding the resignation of President Montero.

That same night, the victorious revolutionaries organized a Government Junta composed of retired General Arturo Puga, Eugenio Matte and Carlos Dávila, with colonel Grove as their minister of Defense.