During World War 2, it was accepted practice to ferry troops to and from combat zones was through any vehicle then available. The primary mover of most armies during the conflict became the multi-faceted "halftrack" which incorporated the frontal drive components of a standard military truck with the rear drive section akin to that of a combat tank. The wheeled/tracked hybrid nature of the design ensured that the vehicle could traverse most operating environments including mud, snow and shallow water sources. However, all halftracks were very basic in their design with protection afforded to the passengers by way of simple armored walls with no standard heavy cover overhead. As such, infantrymen were exposed to the elements (unless a tarp was deployed) and - of course the greater detriment - to both artillery fire and small arms. Regardless, the halftrack remained in use throughout the conflict and was relatively inexpensive to produce while being available in substantial numbers.
For the United States Army, the days of the halftrack as an armored personnel carrier had come to a close following the end of World War 2. Work began on a fully-enclosed, tracked armored vehicle intended to ferry troops in relative safety. The M44 model, designed to carry 24 combat-ready infantry, was born of the T16 pilot vehicle which was based on the chassis of the famous M18 "Hellcat" tank destroyer. However, the vehicle proved much too massive for long term US Army needs and another, more compact, armored vehicle solution was sought.
International Harvester Corporation, an agricultural and automotive concern founded in 1902, was charged with construction of four pilot vehicles utilizing the chassis of the T43 cargo mover. This initiative produced the T18 pilot vehicle which incorporated two remote gun stations, each fitted a 12.7mm heavy machine gun and internal room for up to fourteen personnel. Power was through a Continental AO-895-2 series 6-cylinder air-cooled, gasoline-fueled engine outputting at 295 horsepower. The original T18 was slightly modified in the follow up T18E1 which did away with the remote turrets but added a cupola at the commander's station for improved viewing of the battlefield over the vehicle. T18E2 did away with the cupola altogether and added a machine gun mounting in its place, intended for suppression of enemy forces and cover fire for disembarking/embarking troops. On the whole, the T18 series prototypes was formed from the chassis of the M41 Walker Bulldog light tank which entered service in the early 1950s.
Of the available prototypes considered, authorities selected the T18E1 for formal adoption and serial production began in 1952 under the designation of "M75" (supply catalog designation of "G-620"). The Army commissioned or 1,730 vehicles to be split between production at International Harvester (1,000 units) and Food Machinery and Chemical Corporation (730). The M75 entered service in 1952.