The first American attempt at a printed camouflage uniform came in 1940 when the US Army Corps of Engineers began experimenting with a disruptive-patterned overall that was tested but never issued. By 1942 the USA had joined WWII, and in July of that year the Quartermaster received an urgent request for 150,000 sets of jungle equipment from General Douglas MacArthur, who was high command of US troops in the South Pacific. Fortunately, the engineers had already tested the series of printed camouflage suits dubbed "frog-skin" or "leopard spot", and had shown them to the Quartermaster earlier that month. This pattern was chosen and rushed through testing and approval procedures in order to get the new uniforms out to troops as quickly as possible. US Marine Raiders in the Solomon Islands were the first to receive the new combat uniforms.
Just prior to the Normandy invasion there was a limited experimental issue of HBT camouflage uniforms to elements of the 2nd and 30th Infantry Divisions, the 17th Engineer Battalion and the 41st Armoured Infantry regiment, of the US 2nd Armoured Division. Although the uniform seems to have provided good camouflage for the troops wearing it, the unfamiliar uniforms were often mistaken for the camouflage smocks worn by the German Waffen SS. This resulted in a number of 'friendly fire' incidents. The uniforms were withdrawn from the ETO, although troops were often still issued with the camouflage uniform as their original ones wore out, and period photos show the type in use until well into August 1944; not always with matching sets, as jackets can sometimes be seen mixed with M1937 wool trousers.
Both the US Army and US Marine Corps (USMC) used camouflage uniforms Pacific Theatre of Operations (PTO). (They also both used plain uniforms.) The USMC uniform was totally reversible, which made it well suited to the nature of this theatre of operations, where individual islands could be either sand (Iwo Jima) or dense jungle (Guadalcanal)
The US would later supply the Frog Skin pattern to France who issued it to their 1st and 2nd Foreign Parachute Regiments during the First Indochina War. In 1961, the Cuban Exiles Brigade were issued the Frog Skin pattern by the CIA for the Bay of Pigs invasion. During the early years of the Vietnam War, the US Special Forces often wore incountry made garments using this pattern and also issued it to their Montagnard teams for their guerrilla warfare activities.