Valtteri made his Formula One debut at Albert Park, Melbourne, in the 2013 Australian Grand Prix, thereby becoming the ninth driver from his country Finland to compete at this level. His debut season turned out to be a difficult one – but he at least outscored his team-mate Pastor Maldonado by four points to one. Valtteri’s moment of glory came in qualifying for the Canadian Grand Prix when, on a drying track, he gave a virtuoso performance to claim P3 on the grid. In the race itself, though, he stood no chance against the opposition on a dry track. He therefore had to wait until the penultimate race of the season before scoring his maiden World Championship points for an eighth-place finish in the United States Grand Prix.
After a change of engine supplier at Williams for the 2014 season, Valtteri was back in a Mercedes-powered vehicle for the first time since his spell in Formula 3. He registered his best season so far in the highest echelon of motorsport, claiming six podium appearances and scoring 186 points to finish the campaign in fourth position, behind the Mercedes-AMG Petronas Motorsport duo of Lewis Hamilton and Nico Rosberg and three-time race winner Daniel Ricciardo. That year, Valtteri and his team-mate Felipe Massa secured third place for Williams in the Constructors’ Championship. His best results were two runner-up spots in the British and German Grands Prix.
In the 2015 season, Valtteri once again outscored his team-mate Felipe Massa, despite missing out on the start of the season due to a back injury. He made two podium appearances and finished the year with 136 points. In the 2016 season, his fourth in Formula One, Valtteri secured his team’s sole podium finish, which came in the Canadian Grand Prix. He again came out on top in the internal contest against team-mate Felipe Massa by a score of 85 to 53 points
For the 2017 season, Valtteri became the 11th driver to compete in Formula One with the Mercedes team, following in the footsteps of drivers such as Juan Manuel Fangio, Sir Stirling Moss, Michael Schumacher, Lewis Hamilton and Nico Rosberg. It was a breakthrough year for Valtteri that saw him score his first pole positions (4) and race wins (3). The Finn scored more points in his first season with Mercedes-AMG Petronas Motorsport than in his entire Formula One career before and ended the 2017 season in P3.
2018 proved to be a tougher season, with Ferrari and Red Bull putting up a much more intense fight. It was a season of two halves, with some strong performances early on (narrowly missing out on victories in China and Azerbaijan) before a more difficult second part of the year. He scored eight podiums, two pole positions and seven fastest laps, finishing fifth in the standings – and proving to be a vital part of the team’s triumph in the Constructors’ Championship.