The American Defense Service Medal is a Bronze medallion 1 1/4 inches in diameter. A female Grecian figure is shown on the front holding an ancient war shield and wielding a sword above her head. She is standing upon a oak branch which has four leaves. At the top of the medal are the words "AMERICAN DEFENSE". The words "FOR SERVICE DURING THE LIMITED EMERGENCY PROCLAIMED BY THE PRESIDENT ON SEPTEMBER 8,1939 OR DURING THE UNLIMITED EMERGENCY PROCLAIMED BY THE PRESIDENT ON MAY 27,1941" is inscribed on the reverse of the medal above a seven-leafed spray of laurel.
The Foreign Service clasp is a Bronze bar 1/8 inch in width and 1-1/2 inches in length. It is inscribed with the words "FOREIGN SERVICE", with a star at each end of the inscription. The foreign service clasp is placed on the suspension ribbon of the medal.