In addition to AgustaWestland's manufacturing facilities in Italy and the United States, other companies are involved in the programme, such as the Polish manufacturer PZL-Świdnik, which has produced hundreds of AW139 airframes, and HeliVert, a joint venture between AgustaWestland and Russian Helicopters, which has established a production line inside Russia for the type.

Having performed its maiden flight on 3 February 2001, the AW139 entered revenue service in 2003 and quickly proved itself to be a commercial success.

[10] A key market for the AW139 was the oil and gas industry, which required helicopters of increased endurance for offshore operations.

[12][13] In April 2008, AgustaWestland revealed that it was in the process of certifying an increase in the AW139's max gross weight to 14,991 lb (6,800 kg), to better compete in long-range markets served by helicopters such as the larger Sikorsky S-92 and Eurocopter EC225.

[15] The Philadelphia plant produced its 200th AW139 in September 2014, at which point U.S. production was intended to reach 40 units per year in the near future.

The AW139M is equipped with a high definition forward-looking infrared (FLIR), self-protection system, heavy-duty landing gear, and has low thermal and acoustic signatures.

[17][18] The AW139 serves as the basis for AgustaWestland's wider business strategy, under which it aims to produce a standardised family of helicopters with common design features.

Advances made in the development of new models are intended to be transferable onto existing family members, decreasing the cost of future upgrades for the AW139.

[15][18] In June 2010, it was announced that AgustaWestland and Rostvertol would build a manufacturing plant in Tomilino, Moscow Region, where it was initially planned to produce AW139s by 2012.

[19] HeliVert, a joint venture between AgustaWestland and Rostvertol, began domestic production of the AW139 in 2012, at which point it was planned that between 15 and 20 helicopters would be produced per year.

[23] During 2015, AgustaWestland unveiled an AW139 model with an increased gross weight of seven tonnes, enabling a range of 305 km while carrying 12 passengers.

[24] In November 2015, AgustaWestland demonstrated a 60-minute "run-dry" test (no oil) of an AW139's main gearbox, 30 minutes greater than any other certified rotorcraft at the time.

The FADEC system seamlessly adjusts the engines for pilot convenience and passenger comfort, and can automatically handle a single-engine failure without noticeable deviation.

[27] More than a thousand customizable items of equipment can be configured per customer demand, including auxiliary fuel tanks, rescue hoists, cargo hooks, search and weather radar, ice protection systems, external cameras and searchlights, and seating arrangements.

Although an option on early models, most aircraft include a four-axis autopilot, which allows higher levels of automation and safety and enables advanced functions such as auto-hover.

This level of automation has allowed certification for single-pilot operations under instrument flight rules conditions (SPIFR), and the cockpit can optionally be modified for compatibility with night vision goggles.

[30] Those destined for customers within the Commonwealth of Independent States are typically assembled by a third final manufacturing plant in Tomilino, Moscow operated by HeliVert.

[35] In February 2006, Mitsui Bussan Aerospace signed a $100 million contract for 12 AW139s and an exclusive distribution agreement for the AW139 in Japan.

[41] Heli-One has endeavoured to expand the scope of its MRO in coordination with Leonardo Helicopters, becoming an authorized component repair center by the company, and become approved to perform main gearbox work in April 2021.

[43] In September 2021, the privately owned company Thai Aviation Services arranged the delivery of three AW139s to undertake a multi-year contract to support oil and gas extraction activities in Malaysia.

[45] Qatar-based firm Gulf Helicopters has become one of the largest AW139 operators worldwide, first ordering the type in 2007 for offshore transport duties.

[47] Since taking delivery of their first AW139 in December 2010, Weststar has typically employed the type in support of offshore oil and gas operations.

[49] In March 2022, shortly following the Russian invasion of Ukraine, Leonardo Helicopters suspended its business in Russia and restricted the support available to existing operators of the type in the country.

[28] In May 2016, AgustaWestland parent Leonardo-Finmeccanica announced that Pakistan had signed a contract for an undisclosed number of AW139s as part of a fleet renewal programme spread over several batches, including a logistic support and training package, to perform search and rescue (SAR) operations across the country.

[53] In September 2018, the United States Air Force (USAF) announced that the MH-139, an AW139 variant, was the winner of a competition to replace the Vietnam-era Bell UH-1Ns.

[58] Several rectifiable deficiencies were identified, such as the positioning of the gunner in the cabin fulfilling the specified requirements yet not satisfying reviewing USAF officials.