Born in Turin, Farina was the son of Giovanni Farina, founder of the Stabilimenti Farina coachbuilding firm. He began driving at age nine and took up hillclimbing in 1925, crashing heavily in his first event at Aosta–Gran San Bernardo. A protégé of Tazio Nuvolari, Farina caught Enzo Ferrari's attention and joined Scuderia Ferrari in 1936, where he drove Alfa Romeo machinery. He took his maiden Grand Prix victory at the Naples Grand Prix in 1937 and won three consecutive Italian Championships between 1937 and 1939 with Alfa Corse, including wins at the Coppa Ciano, Grand Prix d'Anvers, and Prix de Berne.
Farina's pre-war career was marked by two fatal accidents involving other drivers. During the 1936 Grand Prix de Deauville he collided with Marcel Lehoux's car, causing Lehoux's death. In the 1938 Gran Premio di Tripoli, László Hartmann's Maserati crashed with Farina's car and Hartmann died the following day.
After World War II Farina returned to Alfa Corse and won the 1946 Grand Prix des Nations. He left the team following internal disputes and raced privately in 1947 before returning in 1948, winning the Grand Prix des Nations and the Monaco Grand Prix. He was re-signed by Alfa Corse for the 1950 season.
The inaugural FIA World Drivers' Championship opened at Silverstone in front of 150,000 spectators. Farina won the race ahead of teammates Luigi Fagioli and Reg Parnell, completing an Alfa Romeo 1–2–3 and becoming one of only three drivers to win on their World Championship debut. He followed with victories at the Swiss and Italian Grands Prix. With teammate Juan Manuel Fangio two points ahead entering the season finale at Monza, Farina needed to win — and did, claiming the title after Fangio's gearbox failed and Piero Taruffi's borrowed car dropped a valve.
Farina continued with Alfa Romeo in 1951 but was outpaced by Fangio, finishing fourth in the championship. His only world championship victory that season came at the Belgian Grand Prix at Spa-Francorchamps. He moved to Ferrari in 1952 when Grand Prix racing adopted Formula 2 regulations, finishing runner-up to teammate Alberto Ascari in both 1952 and 1953. His final Formula One victory came at the 1953 German Grand Prix at the Nürburgring, where he defeated Fangio's Maserati and Mike Hawthorn.
A string of serious injuries plagued Farina from 1954 onwards. He drove with his right arm still in plaster at the 1954 Belgian Grand Prix and required morphine injections to race during the 1955 Argentine season opener. He retired mid-season 1955 following Ascari's fatal accident, and a tyre failure during practice for the 1955 Italian Grand Prix was his final Formula One appearance.
Alongside Formula One, Farina had a distinguished sportscar career with Ferrari. In 1953 he won the 24 Hours of Spa with Mike Hawthorn and the 1000 km Nürburgring with Ascari, both races forming part of the inaugural World Sportscar Championship.
Following retirement from racing, Farina became involved in Alfa Romeo and Jaguar dealerships and worked as an adviser at the Pininfarina factory. On 30 June 1966, while driving to watch the French Grand Prix near Aiguebelle in the Savoy Alps, he lost control of his Lotus Cortina, struck a telegraph pole, and died instantly. He had also been engaged to act as adviser and driving double for actor Yves Montand on the film Grand Prix.
Farina recorded five Grand Prix victories, five pole positions, five fastest laps, and 20 podium finishes in World Championship racing, plus 11 non-championship Formula One victories. His driving style — arms outstretched, body reclined — became one of the defining images of the early championship era, and his 1950 title made him a permanent figure in motorsport history as the sport's first world champion.