[1] These high-end cars were fitted with the 3.0 litre fuel-injected M189 big-block six-cylinder engine, at the time of the model's introduction the company's largest.

They were finished with a higher level of wood and leather trim than the W111, and had standard luxury features such as power steering, automatic transmission, and pneumatic self-levelling suspension,[1][2] an enhancement of the Mercedes-Benz 300d Adenauer's dashboard activated mechanical torsion bar based system.

In the late 1950s, Daimler-Benz AG began plans to unify its entire model range on one platform to take advantage of economies of scale.

With the debut of the clean sheet, top-of-the-range W100 600 still several years off, Mercedes turned to its largest platform, the W111, added the fuel-injected 3-litre six-cylinder M189 engine from the 300d, and supplemented it with luxury features and detailing, to create the W112.

[1] While the W112 was always a very exclusive automobile, its low production numbers reflect a combination of a very high price and limited demand, as it lacked both the size and overwhelming luxury and cachet of the top of the range 300d and 600 limousines which bracketed it.

Upscale versions of the W111 220SE coupe and convertible that had debuted in 1961, their more modern and elegant Paul Bracq designed bodywork lacked the badly dating upwardly-raked and pointed fintails of the sedan, and aged better.

[citation needed] The 300SE sedan was entered in international and European Touring Car Challenge and won several rallies.