Before the inauguration of the Formula One World Championship in 1950, Sanesi accumulated extensive mileage in the Alfa Romeo Tipo 158 — the supercharged 1.5-litre straight-eight voiturette that had been hidden from the occupying German forces during the war, reportedly in a cheese factory in northern Italy, and emerged to resume an unbroken winning run after 1945. As the team's primary test driver, Sanesi developed a granular understanding of the car's behaviour that few race drivers could match. He competed in Grand Prix events with the Alfa Romeo team in this pre-championship period and, on his best days, was among the fastest men on track.
The inaugural Formula One World Drivers' Championship of 1950 ran to seven rounds, of which six were in Europe. The Alfa Romeo works team fielded Nino Farina, Juan Manuel Fangio, and Luigi Fagioli as its permanent trio. For the final European round at Monza in September 1950, the team strengthened its entry by adding Piero Taruffi and Consalvo Sanesi as additional Alfa Romeo 158 drivers, ensuring the title contenders had spare cars on hand should they be needed. Sanesi retired from that race and did not score in 1950.
In 1951 Sanesi drove the updated Alfa Romeo 159 in four Grands Prix. His best championship result was fourth place at the Swiss Grand Prix. He also finished tenth in France and sixth in Britain. He retired from the Belgian Grand Prix. His career total across five Formula One World Championship starts was three points.
Away from single-seaters, Sanesi competed regularly in long-distance and road-race events and found greater scope for results. At the 1953 Mille Miglia he recorded the fastest average speed of any competitor on a single stage — 112.8 mph (181.5 km/h) — surpassing celebrated rivals including Nino Farina and Juan Manuel Fangio. Mechanical failure, however, forced him out before the finish.
At the 1954 Carrera Panamericana in Mexico, Sanesi drove an Alfa Romeo in the European touring car class. At one point during the multi-day event he held the class lead with a cumulative time of 8 hours, 29 minutes, and 24 seconds. He was later overhauled by fellow Alfa Romeo drivers Sergio Mantovani and Mario Della Favera. A couple of days later Sanesi had rebuilt a 17-minute lead, and at that stage Alfa Romeo occupied the top five positions in the European touring car division. He won his class in that event. Sanesi continued to compete in sports car racing into the mid-1960s.
Sanesi's active career came to an abrupt end at the 1964 12 Hours of Sebring. Sharing an Alfa Romeo Giulia TZ with Roberto Bussinello, Sanesi was involved in a crash during the race. His car caught fire. Jocko Maggiacomo, a fellow driver watching from trackside, dived into the flames and pulled Sanesi clear — an act that saved his life. In November 1964, Maggiacomo received a Gentleman of the Road award for his courage, presented by the Milan Automobile Club. Sanesi gave up front-line racing following this incident. He died on 28 July 1998 in Milan at the age of 87.