The CLS marked Mercedes-Benz's return to the executive-size coupe market since the (W124) E-Class Coupe (a two-door sedan) went out of production in 1995. The (W210) E-Class did not spawn a coupe variant, as Mercedes-Benz choose instead to introduce a smaller coupe based on the compact C-Class, the CLK-Class. However, the CLK-Class was built with a lengthened C-Class wheelbase so it could be slotted as a mid-sized vehicle, and it also featured styling cues, engines, and similar pricing to the (W210) E-Class to give the impression that the (W124) E-Class Coupe had been directly replaced.

Marketed as a four-door coupe, the CLS was designed by the American automotive designer, Michael Fink in 2001[2] (born 1967), who styled the first CLK, the C-Sportcoupe, and is known as the stylist who penned the Maybach 57 and 62. According to a Mercedes-Benz press release, the CLS-class was produced to combine the "strong, emotive charisma" of a coupe with the "comfort and practicality" of a sedan. Save for its four-door design, the CLS's design tends towards a coupe, as its sleek roofline reduces the rear passenger room to a 2+2 arrangement, and it offers a smaller selection of engines tending towards high powered of the range, compared to contemporary sedans such as the E-Clas