In 1942, the US Department of Agriculture tested the MB. By 1944, the Allies were confident the war would be won, and wartime production looked to be winding down. This allowed Willys to consider designing a Jeep for the postwar civilian market. Documentation is scarce, but in early 1944, Willys seemed to have found time to start drawing up plans, and one or two prototypes dubbed CJ(-1), for "Civilian Jeep", were running by May of that year. The first CJs had apparently been created by quick modification of the regular military MB, adding a tailgate, lower gearing, a drawbar, and a civilian-style canvas top. The first CJ served as a quick proof-of-concept test, and when a further design evolution materialized, probably became the CJ-1 by default. They were manufactured until the CJ-2s appeared, and they were the first Jeeps built from the ground up for civilian use.

No CJ-1s built have survived, and how many were made is unknown.

Although at least 40 were built, the Willys-Overland CJ-2 was not available for retail sale. The CJ-2s, also known as "AgriJeeps", were the second-generation prototypes for the first production civilian Jeep, and were used solely for testing purposes. Although their design was directly based on the military Willys MB, using the same Willys Go Devil engine — they were not only stripped of all military features, particularly the blackout lighting, but also the CJ-2s had many significant differences in body features and construction versus the military Jeep. They had tailgates, power take-offs, engine governors ($28.65), column-shift T90 manual transmissions, 5.38 gears, 2.43:1 low-range transfer cases, and driver's-side tool indentations. Rear wheelwells were redesigned so that seats could be enlarged, improved, and moved rearward, and new, more weathertight top designs were tried. A canvas half-top with roll-down doors was one of several top designs tried before production. The CJ-2 Go-Devil L-head engine was largely the same as the wartime Jeep, but used a different carburetor and ignition system.

The CJ-2s were built in two main batches, but even within the two groups, each was a little different, as they evolved and were modified for various types of work. For instance a number of experimental combinations of powertrain components were tested. Earlier models were dubbed “pilot models” because they still had so many differences from the production Jeeps. They were painted olive-drab, and had brass “JEEP” badges on the windshield base, the hood sides, and the rear. Some CJ-2s also had an "AgriJeep" plaque fixed to the dash. Later models were stamped "JEEP" and were painted in a few civilian colors that translated into the "WILLYS" stamping and the colors that appeared on the first production CJ-2A Jeeps built from 1945. The spare tire was mounted forward of the passenger-side rear wheel on the earlier models and aft of the rear wheel on later ones. The CJ-2s were likely distributed to "agricultural stations" for evaluation purposes.

Of the 40–45 CJ-2s built, serial numbers CJ2-03, CJ2-04, CJ2-06 (X30), CJ2-09 (X33), CJ2-11, CJ2-12, CJ2-14, CJ2-16, CJ2-26, CJ2-29, CJ2-32 (X56), CJ2-37 (X61), and CJ2-38 (X62) have survived, although some in very rough condition. CJ2-06 and CJ2-09 have been restored.

The lessons learned with the CJ-2 led to the development of the first full-production CJ, the 1945-1949 Willys-Overland CJ-2A, or Universal Jeep. A trademark for "AGRIJEEP" was granted in December 1944, but was not used. The CJ-2A looked very much like a civilianized MB with a tailgate and side-mounted spare wheel. A distinct difference between the MB and the CJ-2A lay in the grilles of the two vehicles. Where the MB had recessed headlights and nine-slot grilles, the CJ-2A had larger, slightly bulging headlights, flush-mounted in a seven-slot grille. While still powered by the reliable L-134 Go-Devil engine, the CJ-2A replaced the MB's T-84 transmission with a beefier T-90 three-speed.

Production of the CJ-2A started on 17 July 1945, sharing production time with the MB – roughly 9000 more MBs were produced through September 1945. Many of the early CJ-2As were produced using remaining stock of the military jeep components such as engine blocks, and in a few cases, modified frames. Up to serial no. 13453, the MB-style full floating rear axle was fitted. Once they were used up, the CJ got a stronger Dana / Spicer model 41. Sometimes the use of MB parts was due to strikes at suppliers, such as Autolite. Since Willys produced few parts in-house and relied heavily on suppliers, it was vulnerable to strikes. Unfortunately for Willys, strikes were common after the war, and this likely contributed to low production totals in 1945 and early 1946.

Since the CJ-2A was primarily intended for farming, ranching, and industrial applications, stock CJ-2As only came with a driver seat and driver side mirror, and a wide variety of options was available, such as: front passenger seat, rear seat, center rear-view mirror, canvas top, front power take-off (PTO), rear PTO, belt pulley drive, capstan winch, governor, rear hydraulic lift, snow plow, welder, generator, mower, disc, front bumper weight, heavy-duty springs, dual vacuum windshield wipers (stock CJ-2As were equipped with a manual wiper on the passenger side and a vacuum wiper on the driver side), dual taillights (stock CJ-2As had a taillight on the driver side and a reflector on the passenger side), hot-climate radiator, driveshaft guards, heater, side steps, and radiator brush guard.

The CJ-2As were produced in lively color combinations that in some ways symbolized the hope and promise of postwar America. True to their intended purpose, the combinations also resembled those used by the most popular farm equipment manufacturers of the day. From 1945 to mid-1946, CJ-2As were only available in two color combinations: Pasture Green with Autumn Yellow wheels and Harvest Tan with Sunset Red wheels. Additional color combinations added in mid-1946 were: Princeton Black with Harvard Red or Sunset Red wheels, Michi…

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