The 124th Cavalry Regiment was organized in 1929 and Federally recognized on March 15 of that year. Previous to its organization, the Texas Cavalry comprised a regiment of six rifle troops (the 112th Cavalry) and the 56th Machine Gun Squadron, brigaded with the 111th (New Mexico) Cavalry as the 56th Cavalry Brigade. It was from the machine gun squadron, plus units of one of the squadrons of the 112th Cavalry, that the regiment, as now constituted, was organized.

The machine gun squadron furnished to the new unit its Medical Department Detachment, Troop B (San Antonio) became the Regimental Machine Gun Troop, Troop A (Brenham) was redesignated Troop E, and its Major, Calvin B. Garwood, now Colonel of the 124th, was assigned as Lieutenant Colonel of the regiment. Troops E and G, 112th Cavalry, Fort Worth, were redesignated A and B, respectively, and became the First Squadron. Service Troop of the 112th (Mineral Wells) was redesignated Troop F, and its Band Section also joined the new regiment. Headquarters Troop was organized at Austin. The regiment was first commanded by Colonel Louis S. Davidson, former executive officer of the 56th Cavalry Brigade.

Only a few changes in organization have occurred in the regiment since its inception. On the retirement in 1934 of Brigadier General Jacob F. Wolters, the regimental commander was promoted to command the brigade, and the executive officer of the regiment, Calvin B. Garwood, became the regiment's second commanding officer. Concurrent with the changes in command Brigade Headquarters Troop at Houston was redesignated and became the Headquarters Troop for the regiment. The Third Squadron, consisting of Troop I at Corpus Christi, and Troop K at Seguin, was organized June 30, 1939.

The history of most of these units begins with the large mass of National Guard cavalry organized in Texas during the World War, for the primary purpose of protection of the Mexican Border. The regiments represented in this background are the Third, Fifth and Seventh Texas Cavalry.

Units and individuals of the regiment as now constituted were on duty under martial law at Borger when it was necessary to supplant the civil authorities in that oil town in 1929; at Sherman in 1930, on the occasion of a race riot there, and in the East Texas oil field when the entire brigade was moved in to enforce the railroad commission's oil production regulations in 1931. Some members of the regiment remained on this last detail for more than a year.

The regiment has the unique distinction of having won all the Pershing Trophies for National Guard marksmanship for Cavalry so far awarded by the National Guard Association. In this achievement, all units of the regiment that were eligible have participated, including those authorized as well as those required to fire the prescribed courses.

The crest of the regiment is described as: On a wreath of the colors, or and sable, a mullet argent, surrounded by a garland of live oak and olive proper; a shield, divided per bend, or and sable; the Spanish motto, Golpeo Rapidamente, which is in English: “I strike quickly.” The motto is truly a shibboleth, being rigidly observed in all phases of training, which stresses celerity in thought, speech and movement.