Räikkönen began competitive karting at age ten and progressed rapidly through national titles in Finland. His first race outside Finland came in Monaco at age fifteen, where he continued after the steering wheel broke, waving it in the air on the home straight to alert his mechanic. He won the British Formula Renault winter series in 1999 and dominated the 2000 Formula Renault UK Championship, taking seven of ten events. Combined across both Formula Renault series, he won 13 of 23 races, a 57 percent win rate that prompted Sauber to offer him a Formula One test at Mugello in September 2000.
Despite having only 23 car races to his name, Räikkönen was granted an FIA Super Licence after Sauber team boss Peter Sauber gave a personal performance guarantee. He scored a championship point on debut at the 2001 Australian Grand Prix — reportedly having been asleep thirty minutes before the race — and finished the season with nine points, helping Sauber to fourth in the Constructors' Championship.
Räikkönen joined McLaren for 2002, inheriting the seat vacated by Mika Häkkinen. He claimed a podium on his debut race for the team and finished runner-up to Michael Schumacher in 2003 by just two points, winning his maiden Grand Prix in Malaysia. The 2004 season was blighted by reliability failures with the MP4-19, but he salvaged a victory in Belgium. In 2005 he won seven Grands Prix and again finished runner-up, this time to Fernando Alonso, earning the F1 Racing Driver of the Year award. A winless 2006 campaign ended with his move to Ferrari, announced after the Italian Grand Prix.
Räikkönen arrived at Ferrari alongside Felipe Massa for 2007 and won his maiden race for the team in Australia, becoming the first driver since Nigel Mansell in 1989 to win his debut Grand Prix for Ferrari. Despite trailing championship leader Lewis Hamilton by 17 points entering the final race in Brazil, Räikkönen won the Brazilian Grand Prix while Hamilton slipped to seventh, clinching the title by a single point from both Hamilton and Alonso — the first three-way title battle decided in the final race since 1986. His six victories were more than either McLaren driver despite finishing equal on points with them. As of the end of the 2025 season, his 2007 title remains the most recent World Drivers' Championship for a Ferrari driver.
In 2008 he took victories in Malaysia and Spain and finished third in the championship. He won the 2009 Belgian Grand Prix — his fourth Belgian victory in five years, earning the informal title "The King of Spa" — before Ferrari replaced him with Fernando Alonso for 2010.
Räikkönen had debuted in rallying at the 2009 Rally Finland and signed with the Citroën Junior Team for the 2010 World Rally Championship season, taking a stage win at Rallye Deutschland. He continued in 2011 as a privateer under the ICE 1 Racing banner, finishing tenth overall in both seasons.
Räikkönen returned to Formula One with Lotus for 2012 and 2013. He won at the 2012 Abu Dhabi Grand Prix — Lotus's first victory since Ayrton Senna's 1987 Detroit win — and won the 2013 Australian Grand Prix from seventh on the grid using a two-stop strategy. He set a new Formula One record of 27 consecutive points-scoring finishes before a brake failure at the 2013 Belgian Grand Prix ended the run. Salary disputes with Lotus, who owed him several million euros by mid-season, led to his departure, along with back surgery that ruled him out of the final two races of 2013.
Räikkönen rejoined Ferrari for 2014, partnering Alonso and then from 2015 onwards Sebastian Vettel. He endured a difficult 2014 and finished a career-low twelfth in the standings. From 2015 he returned to regular podium form. In 2018, his final season with Ferrari, he won the United States Grand Prix at Circuit of the Americas — his 21st and last Grand Prix victory, achieved a record 114 races after his previous win — and finished third in the championship.
Räikkönen moved to Alfa Romeo Racing for 2019 and remained with the team through 2021, retiring from Formula One aged 42. His final race tally of 349 starts is the all-time record for Formula One.
Räikkönen holds several all-time Formula One records: 349 race starts, 46 fastest laps (third-most), and 103 podiums (seventh-most). He also made one-off appearances in the NASCAR Cup Series in 2022 and 2023. Since 2022 he has served as team principal of Kawasaki in the Motocross World Championship.
His understated public persona and unfiltered radio communications became as celebrated as his driving. His 2007 title win, secured with one of the sport's most dramatic final-race comebacks, remains a defining moment in modern Formula One history.