He studied civil engineering at the Rensselaer Polytechnic Institute in Troy, New York, and, in 1871, graduated from the University of Pennsylvania in Philadelphia.

Larrínaga practiced his profession in the United States for some time, returning to Puerto Rico in 1872 where he was appointed architect for the city of San Juan.

In 1880, Larrínaga built the first railroad in Puerto Rico and introduced American rolling stock onto the island.

Larrínaga's involvement in politics began in 1898, when he was appointed Assistant Secretary of the Interior in the Autonomist government.

Larrínaga also served as delegate from the United States to the Third Pan-American Conference held in Rio de Janeiro in 1906.