From a well-to-do family in Reims, Alliot watched racing when he was a child, his heroes being Chris Amon and Graham Hill, but he did not get involved in karting and it was not until he had finished his military service with the elite Chasseur Alpines regiment and was studying political science that he decided to enroll for a course at the Motul racing school at Nogaro, in the south-west of France. He finished second in the Volant Motul competition but Motul was sufficiently impressed to give him some support in Formule Renault in 1976. At his first event Alliot won one heat while a youngster called Alain Prost won the other. But Prost's domination of the series made it difficult for Alliot and his brother Frederic, who was also racing, to survive. They struggled through the 1976 and 1977 seasons but Philippe's efforts were finally rewarded when he was offered a drive with the BP Racing team in 1978. He won the French Formula Renault championship and graduated to French Formula 3 with BP. He finished third in his first season behind Prost and Jean-Louis Schlesser and moved to the European Formula 3 Championship in 1980 but failed to win a race but finished fifth in the series. In 1981 he partnered Alain Ferte in the Martini factory team and won at Magny-Cours and La Chatre to finish third in the series. He stayed on in 1982 but has a less successful year, winning only one race. In 1983 he moved to Formula 2 but hit the headlines that year when he finished third in the Le Mans 24 Hours with Michael and Mario Andretti in a Kremer Porsche. After another difficult year with Martini in Formula 2 he joined the Skoal Bandit RAM Formula 1 team in 1985. He tested for Ligier that winter but went back to Formula 3000 in 1986 with ORECA and won at Spa. After Jacques Laffite was injured at Brands Hatch, Alliot joined Ligier as his replacement before getting a full-time drive with the new Larrousse Lola team in 1987. He stayed with them for three seasons but proved to be fast but rather erratic, having some spectacular accidents. He returned to Ligier for the 1990 season but it was not a success and at the end of the year he took the opportunity to join the Peugeot Sport sportscar team for the 1991 season. This resulted in one victory in 1991 (which he shared with Mauro Baldi) but other good results enabled them to finish third in the Sportscar World Championship. In 1992 the pair won two victories and helped Peugeot to the World Sportscar Championship. This resulted in Philippe being named as a McLaren-Peugeot driver in 1994 in F1 although he only took part in one race for the team after Mika Hakkinen was banned from taking part in the Hungarian GP. In August that year he rejoined Larrousse for one race in Belgium but at the start of 1995 announced his retirement from racing and decided to try a career in politics. He did TV commentary work for a while and also competed in ice racing and on the Paris-Dakar Rally.