Introduced in 1935, the Suburban is among the most enduring American model names. At first , it was essentially an off-shoot of the panel truck, it was fitted with rear windows and rear seats, becoming a heavy duty station wagon. While sales were limited, they were encouraging enough to keep the model in the lineup after the Second World War and into the Advance Design and Task Force eras, with steadily increasing sales as the 1950s progressed thanks to the postwar economic boom and pent-up demand for automobiles of all kinds. It kept on into the 1960s as well, and would be included in the new-for-1960 C-series (and K-series, for four-wheel-drive) trucks.

Marking the first major structural change of the decade, the all-new 1967 GM trucks also included a three-door Suburban. All previous Suburbans were two-doors plus the choice of a tailgate/lift gate or double “barn door” cargo doors in the rear. The new Suburban finally made life easier for passengers in the second row of seats, as the third door was on the curb side for them. Combined with a boom in the camping market, these steps saw sales increase even further.

As part of being a properly equipped tow vehicle, the Suburban also became available in a three-quarter ton rating, in two-wheel or four-wheel drive. The C-20 and K-20 models therefore joined the existing C-10 and K-10 range.

Powertrain availability also paralleled the pickups. From 1967 and 1968, the standard 250 cubic inch six could be optioned out for either a 307 or 327 small-block V-8. For 1969, the 327 gave way for the 350 cubic inch V-8. In addition, the three-quarter tons could also be had with the 402 cubic inch Mark IV big-block (marketed as a 400) from 1970 through 1972.