He saw a need for a Puerto Rican National Guard. Esteves pressured colonial governor Arthur Yager and the colonial legislature about the necessity of a local militia. His request was met with approval. The National Guard Bureau approved this initiative, and on July 19, 1919, the current incarnation of the PRNG was organized. In 1918, he was promoted to Major and by 1919, the first regiment of the Puerto Rico National Guard was formed. After the war, Esteves was sent to Washington, D.C., however his assignment there was cut short and he resigned his commission in the Regular Army because of a medical admonition that residence in a cold climate could have been fatal to his wife. Esteves joined the new entity on February 25, 1920, as commander of the First Battalion of the First Puerto Rico Regiment and its companies. On February 7, 1939, Esteves was named Adjutant General. He was responsible for funneling an increase of new recruits at Camp Tortuguero. In 1942, Esteves was given command of the temporary State Guard.