the person you just mentioned, was he a part of any war?
Yes,  the American Civil War
William McKinley
McKinley was the last president to have served in the American Civil War and the only one to have started the war as an enlisted soldier, beginning as a private in the Union Army and ending as a brevet major. 
what is mckinley birthplace memorial gold dollar? a commemorative coin who struck it? United States Bureau of the Mint who was the designer? Charles E. Barbe and George T. Morgan what design can you see on the obverse and reverse? The obverse of the dollar features an unadorned bust of McKinley, facing left, with the name of the country above and "McKinley Dollar".The reverse is intended to be a facing view of the McKinley birthplace memorial in Niles .
wiki:19666943
William McKinley [SEP] Introduction
As part of the peace settlement, Spain turned over to the United States its main overseas colonies of Puerto Rico, Guam and the Philippines while Cuba was promised independence, but at that time remained under the control of the United States Army. The United States annexed the independent Republic of Hawaii in 1898 and it became a United States territory.