After leaving school (8th grade?) Frank worked in machinery at the Waukesha Motor Company, while Emil worked at the Spring City Foundry. When war broke out in Europe, the Olshefski brothers likely had many conversations with their peers about the pros and cons of military service. They both joined the Marines on May 8th, 1917, just a couple days after Emil’s twenty-second birthday. The brothers were registered in the 6th Marine Regiment, 80th Company. They trained at the United States Marine base at Parris Island, South Carolina.
Frank and Emil departed the U.S. with their company on January 18th, 1918, and arrived in Europe about 2 weeks later, on February 2nd, 1918. It was not a moment too soon. British losses were high and could not support the AEF at all; French forces were also weak. The Olshefskis' company saw brutal action and even participated at the Battle of Belleau Woods. This battle led to the notion that the AEF saved Paris, Belleau Woods was just thirty-nine miles away from the City of Lights; it was the closest the Germans ever got the French capital. Ultimately a U.S. victory, this intense battle brought fame to the U.S. Marine Corps, and helped secure the place of the US in narratives of The Great War.
Frank Olshefski was wounded in combat in July 1918, about a month after Belleau Woods. Did stretcher-bearer Emil carry his brother to the field hospital? It's not clear, but luckily, Frank got treatment and recovered from his wounds.
We don't know what else Frank and Emil did in Europe, only that they were back in Waukesha sometime in 1919. Like many veterans, the brothers returned to their prewar employers, and resumed their daily lives. Within just a few years, only local friends and family knew that 1108 Whiterock Avenue was home to two brave German-American soldiers.