s with its predecessor, the Mark II had a successful rallying career. All models of the Mark I were carried over to the Mark II, though the Mexico gained the RS badge and had its engine changed to a 1.6 L (1,593 cc) OHC Pinto instead of the OHV. A "Sport" model was also produced using the 1.6 L Crossflow. A new model was released, the RS1800, which had a naturally aspirated 1,833 cc (1.8 L; 111.9 cu in) Cosworth BDE DOHC 4 valves per cylinder with a 32/36 DGAV Weber carburetor inline-four engine, producing 117 PS (86 kW; 115 bhp) at 6000 rpm and 171 N⋅m (126 lb⋅ft) of torque at 3750 rpm.[23] It was essentially a special created for rallying.

The works rally cars were highly specialised machines. Bodyshells were heavily strengthened and characterised by the wide wheelarch extensions, and fitment of four large spotlights for night stages. The Cosworth BDE engine was replaced with 2.0 L BDG and gave up to 250 bhp (186 kW; 253 PS) with Cosworth-made aluminium block by 1979. It was complemented by a strengthened transmission, five-speed straight-cut ZF gearbox, five-linked suspension and more minor modifications.

The Mark II Escort continued its predecessor's run on the RAC Rally, winning every year from 1975 to 1979 and racing in a variety of other events around the world. In the 1979 season of the World Rally Championship, Björn Waldegård took the drivers' title, Hannu Mikkola was runner-up and Ari Vatanen finished the year in fifth place, all driving Escort RS1800s.

These drivers' successes throughout the year gave Ford the manufacturers' title, the only time the company had achieved this until the 2006 season, when Marcus Grönholm and Mikko Hirvonen won the title for Ford in Ford Focus RS WRC 06. Vatanen won the drivers' title in 1981, again at the wheel of an RS1800. This victory came despite the arrival on the WRC scene of the four-wheel drive Audi Quattro. Ford placed in the top three in the manufacturers' championship for the sixth year in a row.