The partnership was formed ahead of the 2007 season when defending double World Champion Fernando Alonso joined McLaren from Renault. He was paired with rookie Lewis Hamilton, the reigning GP2 Series champion and a product of the McLaren junior program. Hamilton made his debut at the Australian Grand Prix, finishing third, while Alonso finished second. By the second round in Malaysia, the pair secured a one-two finish for McLaren, with Alonso winning his first race for the team.
The 2007 season saw intense competition between the two teammates as they traded the championship lead. Hamilton became the first rookie to finish on the podium in more than his first two outings, eventually securing nine consecutive podium finishes from the start of the season. McLaren dominated the Monaco Grand Prix, where Alonso won from Hamilton; the pair lapped every driver in the field except for third-placed Felipe Massa.
Hamilton took his maiden victory at the Canadian Grand Prix and followed it with a second consecutive win at the United States Grand Prix after a 300 km/h side-by-side battle with Alonso. By the midpoint of the season, Hamilton held the championship lead, while Alonso remained his primary challenger alongside the Ferrari drivers.
The relationship between the drivers and the team was severely strained during the Hungarian Grand Prix. During qualifying, an incident occurred where Alonso prevented Hamilton from completing his final flying lap. As a consequence, the FIA demoted Alonso to sixth on the grid and ruled that McLaren would be ineligible to score constructors' points for that specific race. Hamilton went on to win the event.
The season was further overshadowed by an espionage controversy involving the illegal usage of confidential technical information belonging to Ferrari. Following the Italian Grand Prix, McLaren was excluded from the Constructors' Championship after being found guilty of theft and illegal usage of confidential technical information from Ferrari. The team did not receive any constructors' points from subsequent races. This allowed Ferrari to clinch the World Constructors' Championship from BMW Sauber at the Belgian Grand Prix following McLaren's exclusion.
The 2007 season marked the first time since 1986 that three drivers—Hamilton, Alonso, and Kimi Räikkönen—entered the final race with a chance to win the title. Hamilton led with 107 points, followed by Alonso with 103 and Räikkönen with 100. At the Brazilian Grand Prix, Hamilton suffered a gearbox problem and finished seventh, while Alonso finished third. Räikkönen won the race and the title with 110 points.
Hamilton and Alonso finished the season tied on 109 points. Under the FIA countback system, Hamilton was awarded second place in the championship because he had recorded five second-place finishes compared to Alonso's four, as both drivers had achieved four race victories during the season. This remains a rare instance of teammates finishing level on points at the top of the standings while losing the title to a third party.