After her January 1914 commissioning, she assisted her sister ship when that ship suffered an explosion in one of her fire rooms in April. After the U.S. entered World War I in April 1917, "Parker" served as an escort for the fourth group of the first American troop convoy of the war. Afterwards, she patrolled the Irish Sea out of Queenstown, Ireland. "Parker" rescued nine survivors of a torpedoed British hospital ship in February 1918, and her crew received accolades from the British Parliament, the Admiralty, and U.S. Navy officials.