The Gran Sport was inspired by an article published by Italian car magazine Quattroruote,^[1] and was built in collaboration with Milanese coachbuilder Zagato.

The first prototype was introduced in April 1965 at a coachbuilders' motor show at the Museo Nazionale dell'Automobile in Turin, while the first production version was unveiled a year later, at the New York Auto Show.^[2]

Alfa Romeo supplied a purpose-built bare chassis to Zagato, where the bodies were hand-built and the cars finished.^[3] Engine, gearbox and other mechanicals were from the 105-series Giulia TI.^[2] The vehicles were sold through Alfa Romeo's dealer network. Alfa Romeo produced 12 chassis in 1965, 52 in 1966, and 29 in 1967.^[4][3]

The 1,570 cc Alfa Romeo Twin Cam inline-four engine produced 92 PS DIN (68 kW; 91 bhp) at 6,000 rpm, for a top speed of 155 km/h (96 mph).^[5] Transmission, suspension and steering were all carried over from the Giulia: 5-speed gearbox, double wishbone suspension at the front and a solid axle at the rear, coil springs, and rack and pinion steering. On aesthetic grounds 15-inch knock-off wire wheels and drum brakes (front three-shoe and rear two-shoe) were fitted instead of the Giulia's steel wheels and four wheel disc brakes. The body was made of aluminium panels over a tubular framework, after Zagato's traditional construction method. The car was available in two versions: "Normale" and "Extra".^[6] As a true roadster, the Gran Sport had removable side curtains and top. There was no boot lid, as a spare wheel was carried at the rear, and the luggage compartment was accessible from behind the seats.