The first American troops, who were often called  Doughboys , landed in Europe in June 1917. However the AEF did not participate at the front until late October 1917, when the 1st Division fired the first American shell of the war toward German lines, although they participated only on a small scale.ne of the most distinguished units was the 369th Infantry Regiment, known as the Harlem Hellfighters. The 369th was on the front lines for six months, longer than any other African-American regiment in the war. One hundred seventy-one members of the 369th were awarded the Legion of Merit.