De Filippis was born on 11 November 1926 in Naples, Italy. She was a keen horse rider in her teenage years.
At the age of 22, de Filippis began her racing career. Two of her brothers told her that she would not be able to go very fast, goading her and making a bet that she would be slow. She won her first race, driving a Fiat 500 on a 10 km drive between Salerno and Cava de' Tirreni. She went on to drive in the Italian sports car championship, finishing second in the 1954 season. Seeing her potential, Maserati brought her in as the works driver.
De Filippis took part in various motor racing events, including hillclimbing and endurance racing, before being given the chance to drive in Formula One. She finished second in a sportscar race supporting the 1956 Naples Grand Prix, driving a Maserati 200S.
Maserati was a successful Formula One chassis manufacturer in the 1950s, supplying several teams and winning numerous races. In 1957 Juan Manuel Fangio won the drivers' title in a Maserati 250F, his fifth and final championship win. The team officially withdrew from the sport at the end of the year but many of the cars remained, being driven by privateers. On 18 May 1958 de Filippis was given the opportunity to enter the Monaco Grand Prix, the second round of the 1958 Formula One season, in one of the 250Fs. Of the 31 entrants only half set a time good enough to qualify, with de Filippis missing out alongside fellow debutant and future Formula One Management and Formula One Administration president Bernie Ecclestone. De Filippis's time of 1'50.8 was 5.8 seconds behind the qualifying time of the fastest 16 which included future world champions Mike Hawthorn, Jack Brabham, and Graham Hill in his first race. Fangio gave de Filippis plenty of advice during the season. In a 2006 interview she recalled that Fangio told her, "You go too fast, you take too many risks."
The 1958 Belgian Grand Prix allowed all drivers to compete with no cut-off for a qualifying time. De Filippis qualified in last place, nearly 44 seconds off Tony Brooks' pole position time. Although she was lapped twice in the 24 lap race she managed to finish, albeit in 10th and last place after nine other cars failed to finish. This would prove to be her only race finish.
At the following race, the French Grand Prix at Reims-Gueux on 6 July 1958, de Fillipis was unable to compete. She claimed in her 2006 interview that the French race director said "The only helmet a woman should wear is the one at the hairdresser's" and that he prevented her from taking part.
De Filippis had a poor result at the 1958 Portuguese Grand Prix in August. She qualified in last place, more than 15 seconds slower than the car ahead of her, and only lasted six laps before her engine failed. On 7 September 1958, she started her home Grand Prix at the Autodromo Nazionale Monza from last place. She completed 57 of the 70 laps before having to retire with engine problems. As the 14th and final retirement out of 21, she could be classified as finishing eighth.
De Filippis joined the Behra-Porsche RSK team for 1959 but again failed to qualify at the Monaco Grand Prix. Her time of 1'47.8 was only three seconds off the lowest qualifying pace and a further one second behind teammate Wolfgang von Trips. It was her final attempt at Grand Prix qualification, though she was still active in motor racing.
1958 was a tragic year in Formula One with the death of several drivers. Porsche team leader Jean Behra died in a racing accident on 1 August 1959 while driving in the sports car support race for the 1959 German Grand Prix at AVUS. De Filippis was supposed to drive at that event and was devastated by deaths of several friends during her time in the sport and especially that of Behra. She left the circuit and turned her back on motor racing for 20 years.
De Filippis married in 1960 and started a family. She kept away from all forms of motor racing until 1979 when she joined the International Club of Former F1 Grand Prix Drivers, going on to take the role of Vice-President in 1997. She was also a founding member of the Maserati Club in 2004 and went on to become its chairperson. De Filippis died in January 2016 at the age of 89.
De Filippis was a pioneer in motor racing, a sport dominated by men, and no woman would race in Formula One for a further 15 years. Fellow Italian Lella Lombardi competed between 1974 and 1976 and remains the only female to have finished a World Championship Formula One race in a point-scoring position. Four other women have since competed in the sport, most recently Giovanna Amati in 1992.