Hawthorn was born in Mexborough, West Riding of Yorkshire, and educated at Ardingly College. His father Leslie owned the Tourist Trophy Garage in Farnham, franchised to supply Jaguar and Ferrari vehicles, and raced motorcycles — an environment that shaped Mike's mechanical instincts and ambitions. After completing studies at Chelsea technical college and an engineering apprenticeship, Hawthorn made his competition debut on 2 September 1950 at the Brighton Speed Trials, winning his class in a 1934 Riley Ulster Imp.
In 1952, having moved to single-seaters, Hawthorn drove a Cooper-Bristol T20 to victory at Goodwood and impressed Enzo Ferrari sufficiently to earn a works drive. He made his Formula One debut at the 1952 Belgian Grand Prix at Spa, finishing fourth.
Hawthorn joined Scuderia Ferrari for the 1953 season and immediately announced himself on the world stage with victory at the French Grand Prix at Reims — his ninth Formula One start. The race has since been dubbed "the race of the century": the top four cars finished within five seconds of each other after 60 laps, with Hawthorn outmanoeuvring Juan Manuel Fangio in the closing stages. He won the BRDC International Trophy and Ulster Trophy that year, and finished the season fourth in the championship.
A heavy crash during the 1954 Gran Premio di Siracusa left him with serious burns, yet he still finished the season third in the drivers' standings, including victory at the Spanish Grand Prix. The death of his father in a road accident that year prompted him to leave Ferrari temporarily and take on responsibility for the family garage.
In January 1955, Hawthorn joined Jaguar, replacing Stirling Moss who had departed for Mercedes. He won the 24 Hours of Le Mans that year after a titanic three-hour duel with Fangio in the early stages, setting a lap record of 4 minutes 6.6 seconds. The race, however, was overshadowed by the worst disaster in motorsport history: a crash involving Hawthorn, Lance Macklin, and Pierre Levegh's Mercedes caused the deaths of 83 spectators. An official inquiry cleared Hawthorn of responsibility, ruling the accident a result of inadequate circuit safety rather than driver error. Hawthorn also won the 12 Hours of Sebring in 1955 with Jaguar.
Rejoining Ferrari in 1957, Hawthorn formed a close friendship with teammate Peter Collins. The 1958 season saw him claim the championship in unusual circumstances: he won only one race — the French Grand Prix at Reims — against four victories by Moss. Two controversial incidents proved decisive. At the Portuguese Grand Prix, Hawthorn faced disqualification for bump-starting his stalled car by rolling it downhill against traffic. Moss, who was leading the race, argued before the stewards on Hawthorn's behalf and the disqualification was reversed. Hawthorn then set the fastest lap on damaged drum brakes to claim an extra point. Those two points, combined with misfortune for Moss during the season, handed Hawthorn the title by a single point.
The victory was shadowed by personal tragedy. Luigi Musso was fatally injured during the French Grand Prix. Peter Collins died at the German Grand Prix two months before the season's end. Stuart Lewis-Evans died from burns following a crash in the final round in Morocco. Hawthorn announced his retirement immediately after securing the title.
Hawthorn was known for his flamboyant personality and his habit of wearing a bow tie while racing — to French fans he became known as "Le Papillon" (The Butterfly). He was gregarious and popular in the paddock, though his friendship with Collins and their reported rivalry against Ferrari teammate Luigi Musso created tensions described years later by Musso's girlfriend Fiamma Breschi as motivating all three to take greater risks on track.
On 22 January 1959, just three months after retiring, Hawthorn died in a road accident on the A3 Guildford bypass near Onslow Village. He was driving his Jaguar 3.4-litre saloon when he clipped a central bollard on a wet bend, losing control, and struck a tree. The impact caused fatal head injuries. He was 29. Hawthorn had already lost one kidney to infection by 1955 and was expected at the time to have only a few more years to live regardless of the accident.
Team manager Rob Walker, who had been driving nearby and was later revealed to have been informally racing Hawthorn at the moment of the crash, had been advised not to elaborate on the circumstances at the subsequent inquest.
Hawthorn was the first of eleven British Formula One World Champions. His record of winning a title with a single race victory in the championship year is shared only with Keke Rosberg, who also won once during his 1982 title-winning season. The Hawthorn Memorial Trophy, established by the RAC in 1959, is awarded annually to the most successful British or Commonwealth driver in Formula One — an honour Lewis Hamilton has claimed eleven times. A statue at Goodwood Circuit commemorates him as Britain's inaugural Formula One champion.