There were some additions to the usual F1 field at Watkins Glen with Team Lotus running a third car for Mario Andretti (who had practiced but not raced for the team in Italy) and Bobby Unser who has suffered a similar fate at Monza in the second BRM. McLaren again ran a third car for Dan Gurney while Ferrari replaced Ickx (who had broken his leg in practice for the Canadian GP) with Derek Bell.

Things did not begin well for Unser who did serious damage to his BRM in the first session. On Saturday, however, Mario Andretti gave everyone a surprise when he put his Lotus on pole position, ahead of Jackie Stewart's Matra. On the second row was Graham Hill in his Lotus and Chris Amon's Ferrari while World Championship hopeful Denny Hulme (who was equal on points with Hill after his win in Canada a fortnight earlier) was on the third row alongside Jochen Rindt's Brabham. Jackie Oliver suffered a wheel failure and crashed the second Lotus heavily. Henri Pescarolo was also a nonstarter when his Matra V12 blew up.

A big crowd gathered in the hope that Andretti would be able to beat the F1 regulars and at the start Mario edged into the lead although Stewart overtook him before the end of the first lap. Amon was able to get into third ahead of Hill while Hulme moved quickly up to fifth place. The order remained stable for the first few laps and then Amon spun and dropped back. On lap 14 Andretti's Lotus was dragging part of the bodywork and he was forced to pit and dropped to the tail of the field. He began to fight back but eventually retired with clutch failure. More significantly, however, Hulme spun on oil and had to pit to have a damaged brake pipe fixed. He eventually rejoined, aiming to pick up points but suffered a driveshaft failure in the closing laps and crashed.

This left Stewart and Hill untroubled at the front and Gurney running third. He dropped behind Surtees after a spin but recovered to retake the position. In the final minutes of the race Gurney had a puncture and so Surtees took third place after all.

The result was a boost to Graham Hill who moved six point clear of Hulme in the World Championship race although Stewart's win put him only three points behind Hill. So it would be a three-way fight for the title in Mexico a month later.