The 190 SL presented an attractive, more affordable alternative to the exclusive Mercedes-Benz 300 SL, sharing its basic styling, engineering, detailing, and fully independent suspension. Both cars had double wishbones in front and swing axles at the rear. Instead of the 300 SL's expensive purpose-built W198 tubular spaceframe, the 190 SL's R121 structure used a shortened unitary floorpan modified from the W121 base saloon.

The 190 SL was powered by a new, slightly oversquare 105 PS (77 kW; 104 hp) Type M121 BII 1.9 L straight-four SOHC engine. Based on the 300 SL's straight six, it had an unchanged 85 mm bore and 4.3 mm reduced 83.6 mm stroke, was fitted with twin-choke dual Solex carburetors, and produced gross 120 hp (89 kW; 122 PS).