Governor Joseph F. Flores
The first war that the United States was involved in wherein Chamorros could be involved as active-duty servicemen was World War I.
Joseph Flores was just in his teens when the U.S. entered the war in 1917. Flores enlisted in the U.S. Navy.
Although he never saw combat, he served in the Navy both during and after the war. He lived for many years in California before World War II.
After that war, he returned to Guam to run many businesses and, most notably, became Governor of Guam in 1960, appointed (as they were in those days) by the U.S. President. That year was a presidential election year, and when John F. Kennedy, a Democrat, was elected President, Flores, a Republican, turned in his courtesy resignation.
Flores passed away in 1981.