The Globemasters are built to the same specifications as those operated by the United States Air Force (USAF), and the Australian aircraft are maintained through an international contract with Boeing.

The aircraft have supported ADF operations in Afghanistan, Iraq and other locations in the Middle East, as well as training exercises in Australia and the United States.

The C-17s are highly regarded throughout the Australian military for their ability to carry large amounts of cargo across long distances, and the process through which they were acquired has been identified as an example of good practice in defence procurement.

To support these operations, the ADF found that it needed long-range aircraft capable of carrying larger loads than could be accommodated in the RAAF's force of Lockheed C-130 Hercules transports.

As a result of this capability gap, the ADF needed to use USAF transports and chartered Russian-built commercial heavy lift aircraft to move supplies and equipment from Australia to its forces in Afghanistan and the Middle East.

[4] Following advocacy from the military, the Australian Government announced as part of an update to its national security strategy in December 2005 that it would consider acquiring heavy lift aircraft to supplement the RAAF's Lockheed Martin C-130J Super Hercules transports.

[4][5] This initiative was one of several measures announced in the government's Defence Update 2005 paper, which sought to better prepare the ADF to operate in locations distant from Australia.

[6] In early 2006 a project office was established within the Defence Materiel Organisation (DMO) to evaluate the options for acquiring heavy lift aircraft.

[2] The USAF provided some of the C-17 delivery "slots" it had purchased to the RAAF to enable the type to rapidly enter Australian service, making them identical to American C-17 even in paint scheme, the only difference being the national markings.

[20] In November 2014 Australia lodged a formal request with the United States Defense Security Cooperation Agency for four C-17s and associated equipment, for a total cost of $A1.85 billion.

[23][24] It was reported in December 2014 that the New Zealand Government was considering purchasing between two and four Globemasters, and Australian Aviation journalist Andrew McLaughlin suggested that any such acquisition would build on Australia's C-17 support infrastructure.

As part of Australia's membership of the Globemaster III Sustainment Partnership, Air Force technicians are responsible for routine servicing, and Boeing handles major maintenance tasks.

Boeing also provides technical support for RAAF Globemasters during deployments outside of Australia, and the company is paid in return for achieving contractually mandated aircraft availability targets.

Maximum loads include 102 passengers, 36 personnel on stretchers, an M1 Abrams tank, three Eurocopter Tiger helicopters or five Bushmaster Protected Mobility Vehicles.

[31] Ian McPhedran, the defence correspondent for News Corp Australia, judged that the C-17s have "changed the game" for the RAAF by allowing the force to rapidly transport large amounts of cargo into combat zones.

[34] According to aviation journalist Nigel Pittaway, the Globemaster's capabilities have made it a highly regarded asset throughout the Australian Defence Organisation.

36 Squadron began a period of intensive training once Corbould delivered A41-206 to Amberley on 7 December 2006, and the unit achieved initial operating capability status in September 2007.

[36] A project to acquire the equipment needed to allow the RAAF's C-17s to be used in the aeromedical evacuation role and develop associated crew procedures began in late 2007.

36 Squadron's structure does not enable it to permanently station Globemasters in the Middle East, the usual practice has been for one of the types to carry a load of cargo from Australia and then conduct missions in the region for several days before returning to Amberley.

[49] In a speech delivered in early 2013, Smith stated that during the previous year the Globemasters had supported operations in the Middle East by flying "60 missions, about 330 hours of flight time, during which the C-17As moved 190 vehicles, 1,800 passengers and over 3,600 tonnes of cargo and conducted 20 aeromedical evacuations".

[15] In December 2013 one of the Globemasters which was deployed to the Middle East was, along with a RAAF Hercules, tasked with flying peacekeepers into South Sudan to reinforce the United Nations force there following an outbreak of fighting.

[56] Following the deployment of Australian fighter aircraft in late 2014 to attack ISIL forces as part of Operation Okra, C-17s also conducted regular flights from Australia to the Middle East carrying munitions and specialised equipment.

[67] Trials to develop the capacity to refuel RAAF Globemasters in flight from the force's Airbus KC-30A Multi Role Tanker Transports began in May 2016.

[15] In January that year the squadron had to evacuate two C-17s from Amberley to Richmond when the base was threatened by rising floodwaters during the Queensland floods; of the other two Globemasters, one was in the Middle East and the other was undergoing maintenance and could not be flown.

36 Squadron transported 100,000 sandbags to Melbourne and flew Royal Australian Navy personnel and vehicles into the state from HMAS Albatross in New South Wales.

[72][73] After the cyclone passed over the Queensland coast, C-17s flew 200 tonnes of groceries into Cairns over a two-day period as part of Operation Yasi Assist.

[74] On 21/22 March, two other C-17s (including one temporarily brought back from the Middle East) flew a large water cannon system from RAAF Base Pearce in Western Australia to Yokota; owned by the Bechtel corporation, the water cannon formed part of the efforts to bring the badly damaged Fukushima Daiichi Nuclear Power Plant under control.

[75] Also in March 2011, Smith stated that the Australian Government would probably provide C-17s to transport humanitarian supplies to Libya if the United Nations requested assistance.

In October 2011 a Globemaster flew a water purification plant to Samoa, from where it was transported by Royal New Zealand Air Force aircraft to Tuvalu.

[79] In July 2014, two Globemasters, several aircrews and maintenance personnel were deployed to Eindhoven Air Base in the Netherlands as part of the response to the shooting down of Malaysia Airlines Flight 17 over Ukraine.