Between 1901 and 1922, he oversaw the management of the Chiclin agricultural negotiation, in which he developed a new social program (school for the children of the operators, as well as houses and sanitation for them).

From the end of the 1910s and throughout the 1920s, he made several trips to the United States and Europe, to study the improvements in the agricultural industry.

Larco Herrera succeeded Colonel Ernesto Montagne Markholz as foreign minister.

In the same year, he acquired the publishing company of the newspaper La Crónica and the magazine Variedades.

And although he later retired from public life, he continued to travel abroad to promote international solidarity and peace in the post-war world.