The regiment participated in the Siege of Santiago until the city surrendered, spent several weeks in Cuba, and was moved back to the United States as a result of disease in August.

As a result of President William McKinley's call for volunteers to fight in the Spanish–American War on 23 April 1898, Massachusetts was given a quota of four regiments.

[4] It was ordered to Tampa, Florida, on 13 May, moving by train to Newport, Rhode Island, where it transferred to the Fall River Line steamer Plymouth, arriving at New York on the morning of the next day.

The regiment continued to Jersey City aboard the transports Vigilancia and Saratoga, completing the movement to Lakeland, Florida by rail on 18 May.

Early on the morning of 23 June, the brigade resumed the advance, arriving at Siboney, a village on the road to Santiago, just before noon.

Company G, which had remained at Siboney in order to unload supplies from the ships, reached the bivouac early the next morning, allowing the advance to be resumed.

[8] During the engagement, the brigade, commanded by Brigadier General William Ludlow, was positioned southwest of the village of El Caney next to the main road.

The regiment was armed with the black powder burning single-shot .45-caliber Springfield rifle, whose smoke revealed their positions to Spanish troops.

They resumed the march at 3:00 am, and the regiment reached the road at El Pozo mill under heavy fire from Spanish snipers, holding positions on a hill at the extreme right flank of the line.

There, the regiment began digging breastworks, using knives, spoons, and mess plates and cups due to a shortage of entrenching tools.