The earliest forerunner of the Hawaii Army National Guard was the Honolulu Rifles a militia formed in 1854.

On January 27, 1893, following the Overthrow of the Hawaiian Kingdom, the National Guard of Hawaii was formed largely adopting men from the Honolulu Rifles.

As a State Defense Force, the Hawaii Territorial Guard was not subject to federalization or deployment, but rather answered only to the governor.

In January 1942, due to suspicions of their loyalty, Hawaii Territorial Guardsman of Japanese ancestry were dismissed.

However, the Japanese members of the Hawaii National Guard who were on Active Duty with the 298th and 299th INF RGTs were retained until June 1942, when they were removed and placed in the Hawaiian Provisional Battalion.

It was redesignated as the 1st Hawaiian Infantry Regiment and mobilized into federal service during World War I at Fort Shafter, Hawaii from 1918-19.

During COVID-19, the Medical Detachment (MED DET) helped distribute vaccines, and successfully executed its Health Service Support and Force Health Protection missions, which aimed to maintain high levels of medical readiness.

They conducted Periodic Health Assessments, Dental Examinations, Hearing Test, Profiles, Vision Readiness Screenings, Immunizations, Flight Physicals, Behavior Health Support, and Case Management Support.