Following his father, Graziano Rossi, Rossi started racing in Grand Prix in 1996 for Aprilia in the 125cc category and won his first World Championship the following year. From there, he moved up to the 250cc category with Aprilia and won the 250cc World Championship in 1999. He won the 500cc World Championship with Honda in 2001, the MotoGP World Championships (also with Honda) in 2002 and 2003, and continued his streak of back-to-back championships by winning the 2004 and 2005 titles after leaving Honda to join Yamaha, before regaining the title in 2008 and retaining it in 2009.
Rossi is first in all time 500 cc/MotoGP race wins standings, with 77 victories, and second in all time overall wins standings with 103 race wins (behind Giacomo Agostini with 122).
All records are correct as of October 24, 2009
At the Netherlands's MotoGP at TT Assen on 27 June, 2009, Rossi became only the second rider to reach 100 Grand Prix wins. He is only behind Giacomo Agostini who has 122 wins, but ahead of Ángel Nieto with 90 wins.
500 cc/MotoGP records: Rossi is
- First in all time race wins standings with 77 race wins.
- First in all time podium standings with 127 podiums in premier class.
- First in most podiums in a season with 16 podiums in 2003, 2005 and 2008.
- First in most fastest laps in a season with 12 fastest laps in 2003.
- First in most points in one season with 373 points in 2008.
- Second in all time premier class world championship wins with 7 world championships behind Giacomo Agostini with 8 titles.
- Second in consecutive world championship wins with 5 consecutive world championships in 2001-2005 along with Michael Doohan with 5 consecutive world championships in 1994-1998, behind Giacomo Agostini with 7 consecutive world championships in 1966-1972.
- Second in all time race fastest laps standings with 63 race fastest laps, behind Giacomo Agostini with 89.
- Second in most race wins in a season with 11 race wins in 2001, 2002 and 2005 along with Giacomo Agostini, behind Michael Doohan with 12 race wins in 1997.
- Third in most pole positions in a season with 9 pole positions in 2003 along with Casey Stoner and Kevin Schwantz, behind Michael Doohan with 12 pole positions in 1997, Wayne Gardner and Freddie Spencer with 10 pole positions in 1987 and 1985 respectively.
- Third in most race wins in a season with 9 race wins in 1999 along with Jorge Lorenzo, Marco Melandri and Max Biaggi, behind Daijiro Kato with 11 race wins in 2001, Anton Mang and Mike Hailwood with 10 race wins in 1981 and 1966 respectively.
- Second most podiums in a season with 12 podiums in 1999 along with Jorge Lorenzo, Marco Melandri, Shinya Nakano, Max Biaggi, Luca Cadalora, John Kocinski and Sito Pons, behind Dani Pedrosa, Tetsuya Harada, Daijiro Kato and Ralf Waldmann with 13 podiums in 2004, 2001, 2001 and 1996 respectively.
125 cc records: Rossi is
- First in most race wins in a season with 11 race wins in 1997.
- Second in most podiums in a season with 13 podiums in 1997, behind Álvaro Bautista with 14 podiums in 2006.
- First in all time points with 4006 points, the only rider to achieve more than 4000 points in the history of the continental circus.
- First in all time podium standings with 163 podiums.
- First in all time pole positions standings with 58 pole positions, the same pole positions number than Michael Doohan.
- Second in all time race wins standings with 103 race wins, behind Agostini with 122 race wins.
- Second in all time fastest laps standings with 83 fastest laps, behind Agostini with 117 fastest laps.
- Third in all time world championship wins with 9 world championships along with Carlo Ubbiali and Mike Hailwood, behind Ángel Nieto with 13 world championships and Giacomo Agostini with 15 world championships.
Other records: Rossi is
- the only rider to win World Championship titles in five different classes: 125 cc, 250 cc, 500 cc, 990 cc & 800 cc.
- the only rider to win consecutive races with different manufacturers. He won the final race of 2003 with Honda at Valencia and the first race of 2004 with Yamaha at Welkom (South Africa).
- the only rider to win championships with the 3 different engines used in MotoGP history, 500cc 2 stroke (2001), 990cc 4 stroke (2002/03/04/05) and 800cc 4stroke (2008/09).
- the only rider to win seven consecutive races at his home Grand Prix at Mugello in 2002-2008.
- the only rider to win three races after starting the race from 11th or lower on the grid (British GP 2001, German GP 2006 & Dutch TT 2007).
- the only rider to win the premier-class title on four different types of motorcycle: A Honda 500cc four-cylinder two-stroke (2001), Honda 990cc five-cylinder four-stroke (2002, 2003), Yamaha 990cc four-cylinder four-stroke (2004, 2005) and a Yamaha 800cc four-cylinder four-stroke (2008, 2009).
- the second rider to win consecutive world championships with different manufacturers (2001-2003 with Honda and 2004-2005 with Yamaha) along with Eddie Lawson (1988 with Yamaha and 1989 with Honda).
- the second rider in history - after Giacomo Agostini - to regain the premier-class crown after two successive defeats.
- Yamaha's most successful rider in the premier class with 44 wins,and 4 titles (2004/05/08/09).
- Aprilia's most successful rider in all classes with 26 wins (12 wins in 125 cc and one title in 1997, and 14 wins in 250cc and one title in 1999).
- From all the active riders, he is Honda's most successful rider in all classes with 33 wins (13 500cc, 20 MotoGP), and 3 world titles (2001 500cc, 2002 2003 MotoGP).
- The only rider to win at least one race per each year for 14 consecutive years.