Born in Orléans, Caillaux studied at the École polytechnique (graduating 12 out of 118) and the École des ponts et chaussées before becoming an engineer, first in Laval, then in Le Mans.

A monarchist, he was a member of the republican-conservative Target group which participated in the overthrow of Adolphe Thiers in 1873.

As minister, he was a supporter of the railway companies and took a special interest in the improvement of the Loire basin.

Caillaux was elected a senator for Sarthe in January 1876, the last of three on the Union conservatrice list.

Caillaux died in Paris in 1896 and was buried in the Père Lachaise Cemetery.