By late 1977, he had caught the attention of Frank Williams as well as Enzo Ferrari. Ferrari had a meeting with him at Maranello, but in the end, Gilles Villeneuve got the drive. Williams, who was looking to rebuild his Formula One racing team. Williams Grand Prix had struggled for success in its first years and after Williams had restarted his team in 1977, Jones was entrusted to give them their first taste of it. As well as Williams, he also signed with Haas-Hall for 1978, and competed in a Lola 333CS in the Can-Am series, winning the title. Jones took nine poles in ten races but missed the Laguna Seca race due to a Formula One scheduling conflict. Stand-in Brian Redman finished twelfth in that race after the kill wire was crimped under a valve cover, resulting in intermittent ignition. Of the nine races in which he competed, Jones won five (Atlanta, Mosport, Road America, Mid-Ohio, and Riverside.) He finished second to Elliot Forbes-Robinson at Charlotte after hitting a chicane and losing a spark plug wire, retired through accident at St Jovite and lost a radiator at Watkins Glen. He finished third at Trois-Rivières after losing a shift fork and being stuck with only second and fifth gears on the tight road circuit. At that race, water-injected brakes were first used in Can-Am, developed by the Haas team and copied with varying degrees of success by others. Jones ran one Can-Am race in 1979 (Mid-Ohio), where he and Keke Rosberg finished 1–2, with Jones winning his last Can-Am start. For Williams, his best result that season was a second-place finish at Watkins Glen. Jones helped put the team on the Formula One map in 1979 using the Williams FW07, after winning four races in the span of five events near the end of the season. Jones finished third in the championship that year, and it was the springboard to an excellent 1980 campaign. Jones's best years in Formula One had just begun, in the middle of the ground-effect era.