Introduced in 1956 and proceeded by the X-Type, the MkI was replaced by the more familiar MkII (also known as the Jaguar Mark 2, Mk2 or Mk 2) in October 1959 and most notably featured better all-round visibility with larger windows. The rear wheel spats disappeared and the rear track was widened, which improved roll-resistance and stability. The dashboard was re-designed with the speedometer and rev counter relocated in front of the driver, with six toggle switches and four engine gauges set across the centre of the car. Independent front suspension was by wishbone and coil springs, with a leaf-sprung live rear axle. This, combined with superior Dunlop all-round disc brakes, and a choice of 2.4, 3.4 and 3.8-litre 6-cylinder XK engines, provided the discerning string-back gloved driver with one of the finest forms of fast and luxurious sports saloons of the sixties. Capable of 125mph in overdrive in 3.8 litre 220bhp form, 0-60 came up in an impressive 8.5 seconds.

Sticking true to the Jaguar moto of 'grace, pace and space', the Mk Jag' was stunning and swift saloon. The 3.8L option used an engine very similar to that in the XKE E-Type Jaguar, albeit with a different inlet manifold, giving the MkII 30hp less than the E-Type, but still enough for stunningly quick preformance. The 2.5L option used an engine from the Daimler V8 that had been previously borrowed form the Daimler SP250 (also known as the Daimler Dart), this engine was particularly light and improved the cars handling characteristics significantly. It is for this reson that the 2.5L models are generally more sought after and collectable, and therefore genreally sell at a higher price.

The Mk II Jag' sold well and gained a reputation for bringing people of all classes inside Jaguar dealerships, since the car was popular with 'old money', city bankers and bank robbers alike (especially since it was vast a big enough for 5 adults). This is reflected in the car's starring role in both The Sweeney and Inspector Morse, both programme's reflecting different sides of the Jaguar's personality. The car was also extremely successful on the track, making a huge impact on the European Touring Car Championship series.

Prices for the Mk II Jag remain high. Although once purchased maintenance isn't too dificult, with parts and accessories readily availible to buy from a plethora of specialist dealers and owners clubs.