Prime contract management is based in Barrow-in-Furness in Cumbria, England, UK, as well as manufacture and assembly of the titanium structures and associated recoil components.

[11][12] The M777 began in 1987 as the Ultralight Field Howitzer (UFH), developed by Vickers' Armaments Division in Barrow-in-Furness, located in Lancashire, England, UK.

[23] The M777A1 and M777A2 use a digital fire-control system similar to that found on self-propelled howitzers such as the M109A6 Paladin to provide navigation, pointing and self-location, allowing it to be put into action quickly.

[24] The Canadian M777 in conjunction with the traditional "glass and iron sights/mounts" uses a digital fire control system called the Digital Gun Management System (DGMS) produced by Leonardo MW with components of the Indirect Fire Control Software Suite (IFCSS) built by the Firepower team in the Canadian Army Land Software Engineering Centre.

[25] The Leonardo MW portion of the system, known as LINAPS, had been proven previously through earlier use on the British Army 105 mm L118 Light Gun.

[27] In June 2012, Golf Battery, 2nd Battalion, 11th Marines, out of Camp Pendleton, California, successfully fired the M982 Excalibur against insurgents at a range of 36 km (22 mi) in Helmand Province, Afghanistan.

[45] Concurrently, the Australian Army has acquired guided 155 mm munitions in the form of the M982 Excalibur and XM1156 Precision Guidance Kit.

[23] In December 2005, 1st Regiment, Royal Canadian Horse Artillery, conducted an inaugural firing of its first 155 mm M777 towed howitzers, for a total of six guns.

The six guns delivered were supplied by the United States Marine Corps under a Foreign Military Sales (FMS) contract[49][unreliable source?]

[citation needed] On 11 May 2012, India's Ministry of Defence formally cleared a proposal to buy 145 guns for ₹30 billion through the US government's Foreign Military Sales (FMS) process.

[74][75] The Indian army used the M777 howitzer in the Himvijay exercise in Arunachal Pradesh which involved the newly raised integrated battle groups.

[78] In April 2022, during the Russian invasion of Ukraine, the United States provided 108, Canada 4, and Australia 6 M777 howitzers with ammunition to the Ukrainian armed forces, to repel Russia.

[29] A Ukrainian officer said in October 2022 that while M777 has to be towed, and has a lower fire rate than the German Panzerhaubitze 2000 and French CAESAR, it is more accurate and easier to use.

[87] Ukrainian Brigadier General Volodomyr Karpenko in a June 2022 interview said that M777 is prone to damage by shrapnel from incoming artillery fire.

In 2014 the US military began fielding several upgrades to its M777 howitzers, including new liquid crystal display units, software updates, improved power systems, and muzzle sensors for onboard ballistic computing.

Future upgrades include a touchscreen Chief Section Display, a new Mission System Computer, and a digital radio.

2nd Platoon, Bravo Battery, 2nd Battalion, 11th Field Artillery Regiment (2-11 FA), was the first US Army unit to fire the M777A in combat in January 2008 in support of Operation Iraqi Freedom.

In August 2017, two soldiers from 319th Field Artillery Regiment were killed from a breech explosion and other members of their gun crew were injured while attempting to fire a M777 at an ISIL mortar position in northern Iraq.

[93] Multiple firing incidents have occurred during training with the M777, including a fatal one in February 2014 with 3-321 FA[94] and previously in 2011 with Marines from Camp Lejeune also at Fort Bragg.

[95] In May 2017, the US Army announced it was buying the Swedish Bofors 155 Bonus round as an interim system as a result of the required phasing out of cluster munitions from artillery shells, complying with policy to achieve less than 1% unexploded ordnance from non-unitary explosives.

The BONUS has two sensor-fused munitions deployed by a 155 mm carrier projectile that scan the ground for targets and fire explosively formed penetrators down from the air.

[100] The Marine howitzers fired every day in support of Iraqi maneuvers, using high explosive, smoke, and illumination rounds.