Sergio Sighinolfi was from Modena. He started working as a mechanic building his own cars. In 1949 he built the Sighinolfi 1100 Sport. It had a tube frame chassis and an aluminum body by d'Oro. It was powered by a Stanguellini prepared Fiat 1100S engine.
Sighinolfi drove the car in the 1950 and 1951 Milla Miglia.
Enzo Ferrari was so impressed with Segio's work that he hired him in 1953 as a test driver. He also participated in a few races. He was the one who crashed one of the new 250Fs into another the day before the shipping of the cars to Argentina in December 1953.
In the 1955 Mille Miglia, Sergio Sighinolfi drove ‘0486M’ as race number ‘724’- representing his start time of 7.24am from the famous Brescia ramp – and bearing the Bologna registration plate ‘BO 46415’. In fact the enthusiastic Ferrari test driver handled this works car brilliantly, powering it all the way round through Pescara, Rome and Florence back to Brescia for an admirable finish in sixth place overall. In this car, his time from Brescia to Rome was recorded as 5hr 33min 23sec, and for the entire 1,000 miles back to Brescia, Sighinolfi clocked 11hr 33min 27sec. Then in October he drove in the Targa Florio sharing the same car with Umberto Maglioli but only completed ten of the eleven laps.
In June 1956 he crashed Fangio's Ferrari into the back of a lorry on the way to Monza for the Supercortemaggiore GP.
Died in a car crash in Saint Venanzio, between Formigine and Maranello, while testing a Ferrari 250 Europa on public roads.