In 1923, Segarra received an appointment to the United States Military Academy at West Point from Horace Mann Towner (1855–1937), who served as Governor of Puerto Rico from 1923 to 1929.

[3] From 1931 to 1932, Segarra served with the 18th Infantry at Fort Wadsworth in Staten Island, New York and with the Camp Dix Civilian Conservation Corps in Burlington County, New Jersey from 1932 to 1936.

[5] On November 25, 1943, Segarra succeeded Colonel John R. Mendenhall and assumed the command of Puerto Rico's 65th Infantry Regiment which at the time was conducting security missions in the jungles of Panama.

[1][5][6] In January 1944, the Regiment was embarked for Jackson Barracks in New Orleans and later sent to Fort Eustis in Newport News, Virginia in preparation for overseas deployment to North Africa.

In 1950, upon the outbreak of the Korean War, Segarra was reassigned and served as troop commander of the men assigned to the 24th Infantry Division who were aboard the USS General E. T. Collins headed for further training in Japan.