Rosberg is the only child of Finnish 1982 Formula One World Champion Keke Rosberg and his German wife. Raised primarily in Monaco and educated at the International School of Nice and the International School of Monaco, he speaks five languages. His father managed his early karting career, during which Rosberg raced alongside a young Lewis Hamilton in the TeamMBM.com karting squad — a partnership that would define the later stages of his F1 career. He won nine races to claim the 2002 Formula BMW ADAC Championship with VIVA Racing at the age of sixteen, becoming at the time the youngest driver to test a Formula One car when Williams rewarded him with a test session at the Circuit de Catalunya.
After two seasons in the Formula 3 Euro Series with Team Rosberg, Nico joined ART Grand Prix — a new team founded by Nicolas Todt and Frédéric Vasseur — for the inaugural GP2 Series season in 2005. ART used a presentation to persuade him away from his preference for BCN Competicion, which had impressed in the preceding International Formula 3000 championship. Rosberg paid around £850,000 for the seat.
He won the sprint race at Magny-Cours for his first series victory, then took feature race victories at Silverstone and the Hockenheimring from pole position. He assumed the Drivers' Championship lead when Heikki Kovalainen, the series' previous leader, finished eighth at Spa-Francorchamps while Rosberg took third. Rosberg secured his position during the season-ending Bahrain round, winning both races there to clinch the inaugural GP2 championship with 120 points.
Rosberg joined Williams for the 2006 season, scoring his first championship points with seventh place at the Bahrain Grand Prix and setting the race's fastest lap — the youngest fastest-lap setter in history at the time, aged 20 years, 8 months and 13 days. He earned his first podiums with Williams in 2008, finishing third in Australia and second at the inaugural Singapore Grand Prix.
He moved to Mercedes in 2010 as a teammate to seven-time world champion Michael Schumacher, where he generally outqualified and outscored the German legend across their three seasons together. Rosberg took his first career race victory at the 2012 Chinese Grand Prix from pole position, then finished second at Monaco. After Hamilton joined Mercedes for 2013, Rosberg won the Monaco and British Grands Prix that year. The following seasons saw him twice finish runner-up to Hamilton in 2014 and 2015 in what the press termed the "Silver War".
In 2016 Rosberg won the first four races of the season to build a 43-point lead, lost the championship lead through the mid-season before wins in Belgium, Singapore and Japan put him back in contention. He entered the Abu Dhabi finale needing only to finish third or better. He secured the title by five points with second place, withstanding Hamilton's attempts to slow the field and allow others to pass Rosberg. He and his father Keke became only the second father-son pairing to both win Formula One World Championships, after Graham and Damon Hill.
Rosberg announced his retirement at the FIA Prize Giving Ceremony in Vienna on 2 December 2016, just five days after winning the championship. He stated he had reached the "pinnacle" of his career, did not want his driving ability to deteriorate, and wished to spend more time with his family. Valtteri Bottas replaced him at Mercedes.
In retirement Rosberg became an eco-entrepreneur and investor in e-mobility companies. He established Rosberg X Racing in 2020 to compete in the Extreme E electric off-road racing series, where the team won the inaugural 2021 constructors' title with Johan Kristoffersson and Molly Taylor as drivers' champions. He also launched the annual Greentech Festival in Berlin in 2019 to showcase sustainable technologies, and became a television pundit for Sky Sports F1, RTL, and Sky Italia. He was inducted into the FIA Hall of Fame in December 2017.
Rosberg's career arc — from the son of a world champion navigating enormous expectation, through the dominant Hamilton era at Mercedes, to a world championship claimed in his final season — is one of the most deliberate and methodical in modern motorsport. His 2005 GP2 championship with ART Grand Prix was the first title in that series' history, and his 2016 retirement the last by a sitting world champion in the sport's modern era.