[1] For surface running, the Electric Boat submarines were powered by two 450-brake-horsepower (336 kW) diesel engines, each driving one propeller shaft.

She was launched on 3 April 1915 sponsored by Mrs. Stephen A. Gardner, and commissioned on 4 May 1916 with Lieutenant (junior grade) Lewis Hancock, Jr., in command.

Following the declaration of war on the Central Powers, the United States Navy dispatched submarines to European waters to protect the Allied shipping lanes.

Following the Armistice with Germany, L-4 departed the Isle of Portland, England, on 3 January 1919 for the United States, arriving Philadelphia on 1 February.

For the next two years, the submarine operated along the East Coast performing experiments developing the tactics of undersea warfare.