Having won various Finnish Karting championships including the ICA Junior title in 2004, the ICA Viking Trophy in 2005, the Formula A and ICA titles in 2006, not to mention the 2006 WSK International Series Formula A title, by 2007 Valtteri was ready for the move up to single-seaters.
In his debut season, the Finnish youngster made an immediate impression, finishing third in the Formula Renault 2.0 Northern European Cup with Koiranen Bros Motorsport and winning the Formula Renault 2.0 UK Winter Series with AKA Cobra. Sadly, though he won three of the four races, Valtteri wasn't eligible for the title because he didn't have an MSA-registered licence.
In 2008 the Finnish youngster continued in the Formula Renault 2.0 Northern European Cup while also contesting the Formula Renault 2.0 Eurocup. In a tour-de-force season with Motopark Academy, Valtteri won both titles, winning an astonishing 12 races in the 14 round NEC and 5 rounds of the Eurocup.
His meteoric rise through the ranks continued in 2009 when he moved up to the Formula Three Euroseries with ART Grand Prix. Though he didn't win any races he finished third overall in the championship with six runner-up finishes and pole positions at Lausitz and Brands Hatch.
He also contested four races in the British F3 Championship, though he was ineligible to score points, and finished fifth in Macau.
On 29 January, Valtteri was confirmed as official test and reserve driver for the Williams F1 team, despite never having sat in an F1 car before.
While former Williams test driver Nico Hulkenberg moved up to a full F1 race seat, it was also confirmed that Valtteri would contest the Formula Three Euroseries with ART Grand Prix.
Despite a strong season, which included two wins and six further trips to the podium, Valtteri could only mange third in the standings, finishing 27 points behind Edoardo Mortara. In addition to his Euroseries exploits Valtteri finished third in the Macau Grand Prix but won the Masters of Formula 3 at Zandvoort, becoming the first person to win the event twice.
Retained as official test and reserve driver by Williams for 2011, Valtteri contested the GP3 Series with ART Grand Prix. After a tough start to the season, he claimed a win in each of the last four race weekends and secured the title by winning the penultimate race ahead of his team-mate.
Having secured the GP3 title, weeks later Valtteri contested the Donington round of the British F3 Championship with Anthony Hieatt's Double R Racing, his win in the second race securing him seventeenth in the overall standings.
Despite not making any appearances for Williams during the 2011 season, Valtteri was soon on the pace in the November Young Driver Test, posting the tenth quickest time. Weeks later, the youngster was confirmed as test and reserve driver for the Grove outfit, with Frank Williams assuring the Finn of at least 15 Friday sessions over the course of 2012.
Sure enough, Frank kept his promise and Valtteri took part in the Friday morning session in all but the Australian, Monaco, Canadian, Singapore and Austin rounds.
Other than a heavy schedule in the simulator, Valtteri also took part in the pre-season test in Barcelona and the mid season test at Mugello and Young Driver Test at Silverstone.
On 28 November, it was confirmed that in 2013 will move up to the race team, the Finn joining Pastor Maldonado. Some sections of the media have been pushing Valtteri as the next big thing, hopefully, the FW35 will allow him to show whether they are right... or not.