A Gold color metal and enamel device 1 inch (2.54 cm) in height overall consisting of a shield blazoned: Per chevron reversed and enhanced Or and Gules, on a pairle Argent fimbriated to chief of the second three fleurs-de-lis Azure, in chief a prickly pear cactus Vert. Attached below the shield a Gold scroll inscribed "PROMPTI ET PARATI" in raised base metal.
The regiment was originally the 1st Illinois Cavalry and as such was mustered into the Federal Service for the Spanish War. The chief of the shield is yellow for Cavalry edged with red which gives the colors of Spain. The Mexican border duty in 1916 is shown by the green cactus. In 1917, it became the 2d Illinois Artillery, this is shown with the red field of the shield, and on being redesignated, the 122d Field Artillery engaged in three major operations in France. These are shown by the three blue fleurs-de-lis.
The distinctive unit insignia was originally approved for the 122d Field Artillery Regiment on 23 July 1924. It was amended to withdraw the crest and render the motto into Latin on 1 November 1924. It was redesignated for the 122d Field Artillery Battalion on 13 November 1942. The insignia was redesignated for the 122d Artillery on 6 January 1961. The insignia was redesignated for the 122d Field Artillery Regiment on 11 July 1972.