Within the A6 family, "G" stood for Ghisa (cast iron, referring to the engine block material) and "CS" for Corsa Sport. The series emerged from Ernesto Maserati's immediate postwar development programme, which had already produced the A6 Sport prototype barchetta in 1946–47. The A6GCS shared the 2-litre engine with the A6G series of road cars but in a substantially higher state of tune and mounted in a purpose-built competition chassis.
The 1,978 cc straight-six engine — 72 mm bore by 81 mm stroke — initially produced 120 hp (88 kW). It was further upgraded in 1952. The car's distinctive single central headlamp earned it the popular nickname Monofaro (single headlamp). Weight ranged from 580 to 670 kg depending on specification.
The A6GCS made its first competition appearance at Modena in 1947 with Luigi Villoresi and Alberto Ascari at the wheel. In 1948 it won the Italian Championship driven by Giovanni Bracco. Between 1947 and 1953, fifteen cars were produced in total, two being exported to Brazil and one to the United States.
By 1953 the car had evolved into the A6GCS/53, a substantially re-engineered variant developed to compete in the World Sportscar Championship. Its engine was improved to produce 170 hp (125 kW; 168 bhp). Bodywork on the /53 was typically a spider, designed initially by Medardo Fantuzzi and then built by either Carrozzeria Fantuzzi or Celestino Fiandri of Carrozzeria Fiandri e Malagoli. Fifty-two A6GCS/53 cars were produced, a number that includes four Berlinettas designed by Aldo Brovarone at Pinin Farina — among the final Maserati designs from that coachbuilder for five decades — and one additional spider on commission from Rome dealer Guglielmo Dei. Vignale also produced one spider. In 1955 Dei acquired two further chassis, numbers 2109 and 2110, and employed Carrozzeria Frua to build open-top versions with A6G/54-sourced engines modified for competition with dry sump lubrication.
The A6GCS sat at the racing apex of the A6 family, which also encompassed the A6 1500 road car (Maserati's first production road car, 61 built 1947–1950), the A6G 2000 grand tourer (16 built, 1950–1951), and the A6GCM single-seater Formula car (12 built, 1951–1953). The A6GCM won the 1953 Italian Grand Prix with Juan Manuel Fangio driving. Racing lessons from both the GCS and GCM fed directly into the Maserati 250F and the follow-on A6G/54 grand tourer, the latter using a double overhead camshaft derivative of the racing engine producing 150 hp.
The A6GCS/53 secured lasting recognition when a surviving example won the Polyphony Digital Award at the Pebble Beach Concours d'Elegance in 2014, an award presented by Kazunori Yamauchi, creator of the Gran Turismo video game series. The recognition highlighted the car's enduring aesthetic and historical significance.
The A6GCS marked Maserati's postwar re-establishment as a constructor of competitive sports racing machinery, bridging the artisanal single-car commissions of the immediate postwar years with the volume sports-racing production that would characterise Maserati through the mid-1950s.