When the formation of the Latvian Riflemen battalions begun in 1915 he was appointed to command the 1st Daugavgrīva battalion. He and his men participated in battles near the Misa River, and near Ķekava. In March 1916 Briedis was severely wounded in the jaw, but he recovered and participated in the Christmas Battles as commander of a battalion. During the Christmas Battles he fought in Tīreļpurvs, where he was wounded for a second time.