The first generation made its debut at the Tokyo Motor Show in October 1981, and was launched in May 1982. Initially, it was a three-door, short-wheelbase model available with a metal or canvas top and three different engines options, although more were gradually added, ending with a 3-litre V6 on top of the range.
It was loaded with features that had previously not been seen on a Japanese four-wheel-drive car: a turbocharged diesel engine, a front double wishbone suspension with torsion bar springs, power steering and suspension seats. This made the Pajero a four-wheel-drive vehicle which integrated all the amenities of a passenger car.
In January 1983, only a year following its launch, mildly tuned production Pajeros entered the world of motor sport. The Pajero, however, failed to appeal to everyone. In Japan it was seen as a commercial vehicle, and since it was only available in a short-wheelbase form, it didn’t really appeal to those with families.
Hence, in February 1983, Mitsubishi came out with a long-wheelbase, five-door model, to serve the needs of a larger target market. The long-wheelbase model was available with a choice of two different engines; a 2.0-litre turbocharged petrol (badged as "2.0 Turbo" and "2000 Turbo" in some markets) and a 2.3 liter turbocharged diesel. It also came in Standard, Semi-High Roof and High Roof body styles. A stripped down nine-seater version of the High-Roof variant was commonly used in UN Peace Operations.
The long-wheelbase model also increased seating capacity to seven, with available third row seats, which could be folded to the sides for additional trunk space or combined with second row seats to form a bed.
The Pajero was further refined in June 1984. The turbo diesel engines now had higher power/torque ratings, whilst the long-wheelbase models got standard four-wheel disc brakes and four-way adjustable shock absorbers as standard equipment.
A new flagship model was then introduced in early 1987, with a two-tone paintjob, fifteen inch (38 cm) light alloy wheels, front-seat heaters, wool seat covers, genuine leather headrests, a three spoke steering wheel and a sound system with radio/cassette. Also in 1987, a version of the Pajero/Montero was rebadged byDodge as the Raider, which ran through 1989.
Finally in 1988, a 3.0-litre SOHC V6 engine was made available, alongside a 2.5-litre turbo diesel engine, with the first 4x4 intercooler. This translated to better acceleration in mid to high rev ranges. The long-wheelbase models got a coil link suspension system for better ride comfort and off-road ability.
It was available with a 3-door body for a short wheelbase (SWB) or a 5-door body for a long-wheelbase (LWB). Engines included a 2.6 L I4 with 82 kW (110 hp/112 PS), a 3.0 L V6 with EFI and 104 kW (139 hp/141 PS) and a turbocharged 2.5 L OHV diesel I4 with 62 kW (83 hp/84 PS) or an intercooled 70 kW (94 hp/95 PS). Part-time four-wheel drive was standard on all models.
The Gen I platform was later built under license by Hyundai Precision Products as the Hyundai Galloper from 1991 to 2003, and exported to Europe for a brief time. While it used first generation mechanicals, the Galloper's body was closer to the second generation Pajeros.