In the mid-1970s, Embraer had already achieved worldwide recognition and was beginning to evaluate the possibility of establishing partnerships with foreign companies in order to enable research and eventual technology transfer.

The first studies that moved in this direction began in 1976, in conjunction with the Italian company Macchi, which at the time already had an advanced jet project. The following year, the project designated MB 340 was launched.

Subsequently, to meet the needs of the Italian Air Force, a partnership was formed between Aeritália (now Alenia) and Macchi (now Aermacchi), launching the AMX subsonic fighter program in 1978 (with the name derived from A for Aeritália, M for Macchi, and X for experimental). Embraer was to account for one-third of the program and costs, taking responsibility for the wing sections, empennage, and structural fatigue testing. Aermacchi was responsible for the remaining two-thirds, producing the fuselage and onboard systems, as well as conducting static and armament tests.

After a period during which work was suspended, Brazilian aviation authorities reaffirmed the decision to participate in the Italian program while attending the Farnborough Airshow in England in 1980. Brazil's participation was officially formalized a few months later, on March 27, 1981, through an agreement signed between the two countries.

Following contractual adjustments, Embraer’s share of the program was set at 30%, with the Italian companies holding 70%. Embraer was tasked with developing and manufacturing the wings, engine air intakes, horizontal stabilizers, underwing pylons ("weapon stations"), and fuel tanks. Furthermore, the company played an active role in the design of the landing gear, navigation and attack systems, flight controls, and weapon control systems. Two flight-test prototypes and one fatigue-test airframe were built and subjected to testing in Brazil.

The AMX was designed as a single-engine, single-seat aircraft specialized in attack missions, prioritizing robustness and reliability for high-exposure scenarios. It featured long range—compatible with the country's continental dimensions—and incorporated in-flight refueling technology, advanced computing, navigation, and attack systems, as well as electronic countermeasures. Among other innovations of the time, it featured a flight control system with an augmentation system and HOTAS (Hands-On Throttle and Stick) operation for navigation and attack. A two-seat variant was subsequently developed for pilot operational conversion (OCU) for this type of aircraft.

As a fighter-attack aircraft, the AMX offered lower costs than its competitors while being efficient and technologically advanced. It accommodated a single pilot in an ejection seat. The subsonic jet was powered by Rolls-Royce engines; capable of reaching speeds of 750 km/h, it was also an "invisible" aircraft—meaning its Electronic Countermeasures (ECM) unit emitted continuous signals to confuse radar or other types of sensing systems.

The aircraft's official unveiling took place in Italy in May 1985, and the first AMX prototype built in Brazil—the fourth in the program—was rolled out and made its first official flight in October of that year. In 1988, the first serial-production AMX flew in Italy, and the first delivery to the Brazilian Air Force (FAB)—which acquired a total of 54 aircraft across three batches—took place on October 17, 1989.