Visually the early versions were identical in exterior appearance to the Mark VIII except for the addition of a chrome "Mk IX" badge to the boot lid.

Later versions had a larger tail-lamp assembly with an amber section for traffic indication, visually similar to the tail-lights of the smaller Jaguar Mark 2.

The Mark IX was the first production Jaguar to offer four-wheel servo-assisted Dunlop disc brakes and recirculating ball power steering, which were now standard equipment.

The torsion bar independent front suspension and leaf-sprung rear live axle were retained from the Mk VIII, which, in turn, was first used in the 1949 Mark V. Final drive was 4.27:1, (4.55:1 when overdrive was fitted).

Autocar magazine tested a Mk IX Automatic in its Used Cars on the Road series, number 200, published in the edition dated 14 December 1962.

When Charles de Gaulle paid a state visit to Canada in 1960, the official cars for the motorcade were Mark IX Jaguars.

The Nigerian government bought forty Mark IXs, painted in state colours of green and white.

The impressive Jaguars of the 1950s were sufficiently popular in western Africa that "Jagwah" survives to this day as a colloquialism for "smart man-about-town".