For 25 years from Head was technical director at Williams Grand Prix Engineering, and responsible for many innovations within Formula One. Head oversaw the design and construction of Williams cars until May 2004 when his role was handed over to Sam Michael. Frequently blunt and outspoken, Head has a formidable reputation for speaking his mind to both employees and the press, making him a highly popular figure in the sport.
Head was involved in a number of new projects all trying to become established as car builders or engineering companies and it was during this period that Head and Frank Williams met. Finally becoming disillusioned by his lack of success Head quit motor racing to work on building boats.
In 1976 thirty-four year old Frank Williams decided that the time was right to start his own team and promptly set about luring Head back into Formula One. After one abortive attempt, on February 8 1977, Williams Grand Prix Engineering was founded with Williams and Head taking seventy and thirty percent of the company respectively. In the team raced a customer March chassis, but in , with backing from Saudi Airlines and having signed Australian driver Alan Jones, the Patrick Head-designed FW06 made its first appearance. Despite having no money, and with Williams himself frequently forced to conduct business from a telephone box, Head still managed to design a respectable car.
The following season Williams scored 11 world championship points finishing 9th in the constructors championship and from here momentum began to build. As early as the fourth round of the season Jones made the team's first visit to the podium. The same year saw a Head designed car take the first of over one-hundred race wins at the British Grand Prix. Four more victories followed in and Patrick Head was now an established Grand Prix car designer.
In 1986 Patrick Head, with other Williams management, was forced to assume control of the team when Frank Williams was seriously injured in a road accident. Despite this diversion, and under Head's temporary stewartship, the team still secured the constructors titles in and both the constructors' and drivers title (with Nelson Piquet) in .
Perhaps the most fruitful of all his associations with upcoming engineers began in 1990 when Williams hired Adrian Newey, recently sacked as technical director of Leyton House. The two engineers rapidly formed the outstanding design partnership of the 1990s with Head/Newey cars achieving a level of dominance never seen before, and not repeated until the Ferrari/Schumacher era a decade later. In a seven year period between 1991 and 1997, Williams had fifty-nine race wins, won five constructors titles, and four different drivers won world championships. However, Newey also had ambitions to succeed to technical director, but this was blocked as Head was a founder and shareholder of the team. With Williams securing both the drivers and constructors titles in 1996, McLaren managed to lure Newey away though he was forced to take gardening leave for the 1997 season.
Since the departure of Newey, Williams have often appeared a spent force, able to win occasionally, but unable to mount a consistent challenge. During the dominant Ferrari/Schumacher period from 2000-04, Williams managed to finish runner-up in the constructors championship in 2002 and 2003, and 2003 was the closest that one of their drivers, Juan Pablo Montoya, got to the world title.
Finally in 2004 came the news that Patrick Head was to stand down as technical director in favour of thirty-three year old Sam Michael. Head's move to Engineering Director was widely seen as demotion and final acceptance by Sir Frank Williams that he was no longer able to bring the team the level of success it had once enjoyed.