Shortly after the United States entered World War I, the regiment was constituted in the National Army on 18 May 1917, and organized on 5 February 1918 at Camp Fremont.

The distinctive unit insignia included a 1 1/8 in (2.86 cm) gold colored metal and enamel device, which consisted of a yellow shield divided by a red stripe with a horse's head above it in the upper right and a walking bear below in the lower left.

The shield's color symbolized the cavalry, the red stripe represented its artillery service, the horse's head was from the Coat of arms of New Jersey, where the regiment was allocated, and the bear was from the Seal of California, where the 302nd was originally formed.

The regimental motto, "Celer Eundo; Concurso Ferox" (Swift in March; Bold in Attack), was attached to the bottom of the distinctive unit insignia.

The regimental coat of arms was of a similar design to the distinctive unit insignia but included the Organized Reserve's Minuteman crest above the shield and omitted the motto.