Shortly after the United States entered World War I, the regiment was constituted in the National Army on 18 May 1917, and organized on 3 February 1918 at Camp Fremont.

[4] From 1 March 1922 to 19 June 1925, the regiment was commanded by Colonel William J. Donovan, the future head of the Office of Strategic Services.

[2] After the United States entered World War II, it was converted into the 542nd Signal Aircraft Warning Regiment on 30 January 1942.

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 with a red chevron in the center, a red star to the left of a walking grizzly bear in the upper left corner, and a beaver below the chevron.

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.