It was developed to meet a NATO Basic Military Requirement 4; accordingly, it was originally designed with lift engines for a V/STOL capability, but these were never fitted to production aircraft.

No wider NATO production contact were emerged, but Italy was keen to support its homegrown transport aircraft and issued an order for it in a more conventional configuration.

Following its introduction to Italian Air Force service in April 1978, the type soon proved itself to be capable for conducting operations from compact and austere airstrips, particularly humanitarian missions.

Libyan efforts to purchase 20 G.222s were initially vetoed by United States; Libya later procured a version of the aircraft without US-made equipment present instead.

[5] None of the submissions resulted in a production contract; however the Italian Air Force (AMI), who was at the time seeking a replacement for the Fairchild C-119 Flying Boxcar, felt that the Fiat Aviazione proposal had merit, and placed an order for two prototypes and a ground-test airframe in 1968.

[6][7] The G.222 was substantially redeveloped from the NATO submission, the V/STOL lift engines having been omitted completely and the conventional Dart engines replaced by a pair of General Electric T64s;[6] the twin-boom tail featured on the V/STOL concept was also eliminated and replaced by a more conventional single tail configuration; subsequently the new aircraft had no V/STOL capability but retained considerable short take-off/landing (STOL) performance.

[9] In December 1971, the Italian Air Force, who had placed a provisional order for the developing type, formally began evaluating the G.222 and the performance of the two prototypes then in service.

[11] Following on from its introduction by the AMI, the G.222 was procured as a tactical transport aircraft by various international customers, including Argentina, Nigeria, Somalia, Venezuela and Thailand.

[12] In December 1978, Aeritalia elected to transfer final assembly of the G.222 from Turin to Naples, at which point a total of 44 firm orders had been obtained for the type and one aircraft per month was being manufactured.

[12] In July 2005, the Nigerian Air Force signed a $74.5 million contract with Alenia Aeronautica for the refurbishment of a total of five G.222s, as well as the purchase of a retired AMI G.222.

[14][20][11] The cargo deck has a large rear ramp, allowing the loading of palletised goods and vehicles, as well as sliding doors on either side of the fuselage, which are capable of being used to deploy paratroopers.

[22] In part due to the austere maintenance requirements of the G.222 and its capability of operating from short unprepared airstrips in remote regions, it has seen heavy use for performing various humanitarian missions across Africa, East Asia, Europe and Central America.

[25] On 3 September 1992, an Italian Air Force (Aeronautica Militare Italiana) G.222 was shot down when approaching Sarajevo airfield while conducting a United Nations relief mission.

[26][27][28] In November 1999, the Italian Air Force placed an initial order for twelve new-build aircraft of an upgraded G.222 derivative, designated as the C-27J, as a replacement for their existing G.222s.

Ballistic protection, adaptations for serving in the conditions of Afghanistan, and many new avionics systems, including a digital auto-pilot, were installed; two aircraft were also configured for VIP transport duties.