During the Spanish–American War, as a private in the United States Marine Corps he was stationed on the armored cruiser USS Brooklyn, which served as the flagship of Commodore Winfield Scott Schley during the Battle of Santiago de Cuba on July 3, 1898.

He had to crawl along the gun's barrel and expose himself to "murderous fire from the enemy batteries",[3] in addition to having to contend with the blasts from the forward turret, which nearly knocked him overboard.

[4] The American fleet sustained casualties of only one dead, Chief Yeoman George H. Ellis (1874–1898) of the Brooklyn, and two wounded; Lt. J.P.J.

MacNeal received the Medal of Honor on August 9, 1899, almost a year to the day after the war ended.

A strange incident transpired five years later, where he re-enlisted on 4 January 1906 into the Marines at the New York navy yard, but was considered "deserted" with the transcription note mentioning that he failed to show up for assigned duty at Portsmouth Navy yard in February of the same year.

As a civilian he had worked primarily as a department store manager in New Jersey since the early 20th century.