The M1A1 was fitted with a new turret armed with a 120mm gun derived from the Rheinmetall design found in Germany's Leopard 2. The ammunition stowage was reduced with the larger 120mm rounds, and the ammunition stowage on the turret floor was eliminated. Six rounds are stowed in the hull, with the remainder in the turret bustle. During production, the design of the rear track skirt was changed and the track retaining ring was deleted. Late-production M1A1s had holes in the turret roof for the installation of a commander's independent thermal viewer, which showed up on the M1A2. Also introduced during the production run was an eye-safe carbon dioxide laser that was able to operate under the same conditions as the gunner's TIS, and steel-encased depleted uranium was added to the tank's armor starting in October 1988. The driver of the M1A1 was provided with a mechanical override for the engine and transmission's protective shutdown measures in 1986. This allowed the driver to operate the tank when the engine's management system would otherwise have shut the engine and transmission down, which would be a potentially dangerous situation in battle. This system was known as the shift hand actuated fuel transmission system (SHAFTS), and allowed the engine to work up to 400hp. The M1A1 was also fitted with an overpressure NBC system, and a microclimate cooling system cooled the crewmembers, but not the entire crew compartment. The US Army received 4796 M1A1s, the US Marines bought 221, and Egypt co-produced 555 with an order for an additional 200. When the Marines acquired the M1A1 to replace their aging M60A1s, their requirements led to a tank with more tie-down points, mounting points for a deep-water fording kit, and a position locating system. Tanks with these features and the depleted uranium armor were dubbed M1A1HC, for Heavy Common. The M1A1HC also saw use of a turret bustle-mounted external auxiliary power unit.

A digital applique command and control package was installed in the M1A1, resulting in the M1A1D. M1A1s also underwent overhaul to factory standards in an effort to reduce maintenance costs, and this program was dubbed the Abrams Integrated Management (AIM) progam. The Marines awarded a contract to equip their M1A1s with a second-generation thermal sight in the Firepower Enhancement Package (FEP) program.

The M1A2 gave the tank commander an independent thermal viewer, allowing the crew to use hunter-killer tactics where the commander could scan for targets while the gunner was already engaging. The TC's weapon station in the M1A2 was changed to a non-rotating cupola with a manually-operated mount for the .50cal MG. The M1A2 was also fitted with an intervehicular information system (IVIS), which allowed digital transmission of data between friendly units. A digital data bus and central processing unit assited with the acquisition and dissemination of data. Most M1A2s have been created by modifying older M1 tanks.

The M1A2SEP, or systems enhancement package, features improved computer processors, color displays for the crew, a higher-resolution second-generation forward-looking infrared sight that replaces the TIS, an under-armor auxiliary power unit (UAAPU), and a thermal management system. The UAAPU replaces the external APU found on older Abrams tanks, and provides electrical power to the vehicle without having to run the thirsty main engine. The UAAPU is powered by a turbine engine using the same fuel tanks as the tank's main engine, and is located in the left rear sponson. The thermal management system provides air conditioning to keep the crew compartment under 95°F (25°C) and the temperature of the electronics under 125°F (52.7°C). The driver also received an integrated display in the SEP improvements.