Lorenzo made his championship debut on his fifteenth birthday, on the second qualifying day for the 2002 125cc Spanish Grand Prix, after having missed Friday practice, due to not being old enough to race (minimum age regulations).

In doing so, he became the youngest rider in MotoGP to finish on the podium in his first three races,[13] taking the record from compatriot and rival[14] Dani Pedrosa by a single day.

At both Donington Park and Assen, he was observed to be riding more conservatively after a series of injuries, but moved up the order in the later part of the race to finish 6th in each case.

[18] Lorenzo suffered yet more injuries to his feet at the USGP at Mazda Raceway Laguna Seca on 20 July, when he experienced his seventh crash in only three months.

His season started well, with two wins – at Motegi[19] and Le Mans[20] – and two more podiums out of five races, leading the championship up until that point after which Valentino Rossi stole the momentum from him in the Catalan Grand Prix.

As a consequence of a crash in qualifying at the Laguna Seca round, Lorenzo suffered a small fracture in the head of the fourth metatarsal in his right foot, contusions to the bones in both ankles and damage to his collarbone in his right shoulder.

On 25 August 2009, Lorenzo ended speculation surrounding a possible move to Honda or Ducati by signing a contract to race with Yamaha in the 2010 MotoGP Championship.

[27] Ducati reputedly offered him a $15 million contract to take the seat vacated by Marco Melandri which was eventually taken by Nicky Hayden.

[36] After successive second places at Jerez and Estoril,[37] Lorenzo then won the next two races at Le Mans,[38] and Cataluña; in the process, opening up a 20-point lead over Casey Stoner in the riders' championship.

[39] Ahead of the British Grand Prix, Lorenzo signed a new two-year contract with Yamaha, keeping him with the team until the end of the 2014 season.

[42] After being taken out of the Dutch TT by Álvaro Bautista[43] and a second place at the Sachsenring, Lorenzo recorded his fifth win of the season at Mugello to extend his championship lead to 19 over Dani Pedrosa.

Starting the second half of the season, Lorenzo achieved four consecutive second-place finishes at Indianapolis, Brno,[58] Silverstone[59] and Misano.

[63] For the majority of the season, Lorenzo was involved in a three-way rivalry with teammate Rossi and Dani Pedrosa to claim the runner-up position overall.

Before his first runner-up finish at the Spanish Grand Prix in Jerez, Lorenzo announced that he would leave the Yamaha team to join Ducati next season.

However, he wrapped up the season at Valencia not only with a qualifying lap record and his 65th career pole but with a win in his final race with Yamaha.

After yet another difficult season opening blighted by a brake failure in Qatar and a collision while fighting for a podium at Jerez, it was announced Lorenzo's contract would not be renewed for 2019.

Following the latter crash which broke a bone in his foot, Lorenzo withdrew from the Japanese[89] MotoGP and Australian Motorcycle Grand Prix at Phillip Island.

On 6 June 2018, it was announced that Lorenzo would join Repsol Honda Team on a two-year deal, replacing retiring compatriot Dani Pedrosa.

[91] Despite tough early going in the season, finishing no higher than 11th, Lorenzo presented positive development of the Honda for his riding style coming into the mid-season.

At the Assen GP, Lorenzo suffered a tumble in the gravel during the first practice session and fractured two vertebras[92] which eliminated him from race contention.

Later in the year, Lorenzo revealed that he opted against making a permanent comeback within the Ducati stable for the 2021 season after serious considerations, also endorsing Francesco Bagnaia as the 'logical choice' to fill the factory seat in his place.

Those included Lorenzo imitating a Spaceman, jumping into the lake in the infield of the Jerez circuit, and Nintendo's Mario brothers making an appearance at the trackside.

Simoncelli retorted by reminding Lorenzo of his race suspension after he was overly aggressive while overtaking a rider in 2005, which included last lap clashing of fairings with Pedrosa and moments later taking Alex de Angelis down.

Simoncelli put even more fuel to the fire by saying, "I will be arrested", to which a visibly angry Lorenzo reacted by saying, "This is no joke, we are playing with our lives here".

Simoncelli claimed that he still had his leathers which were left blackened at the knee slider after a previous incident with Lorenzo at the final round of the 2010 season.

[104] Driving the #911 Porsche "VIP" car, Lorenzo finished 30th in the Supercup race; being a guest driver he was ineligible for points.

Lorenzo signed a multi-year deal[108] with Lazarus Corse in 2024 to race an Aston Martin Vantage GT3, with an announcement made on Instagram.

[110] During a break between the Italian and British rounds of the 2010 Championship, Lorenzo rode a Yamaha in a parade lap around the world-famous Snaefell Mountain Course at the Isle of Man TT.

[114] Lorenzo wore sponsored helmets from the Call of Duty franchise, at the Valencian Grand Prix in 2013 for Ghosts and Advanced Warfare in 2014.

(key) (Races in bold indicate pole position) (Races in italics indicate fastest lap) 1949  L. Graham 1950  U. Masetti 1951  G. Duke 1952  U. Masetti 1953  G. Duke 1954  G. Duke 1955  G. Duke 1956  J. Surtees 1957  L. Liberati 1958  J. Surtees 1959  J. Surtees 1960  J. Surtees 1961  G. Hocking 1962  M. Hailwood 1963  M. Hailwood 1964  M. Hailwood 1965  M. Hailwood 1966  G. Agostini 1967  G. Agostini 1968  G. Agostini 1969  G. Agostini 1970  G. Agostini 1971  G. Agostini 1972  G. Agostini 1973  P. Read 1974  P. Read 1975  G. Agostini 1976  B. Sheene 1977  B. Sheene 1978  K. Roberts 1979  K. Roberts 1980  K. Roberts 1981  M. Lucchinelli 1982  F. Uncini 1983  F. Spencer 1984  E. Lawson 1985  F. Spencer 1986  E. Lawson 1987  W. Gardner 1988  E. Lawson 1989  E. Lawson 1990  W. Rainey 1991  W. Rainey 1992  W. Rainey 1993  K. Schwantz 1994  M. Doohan 1995  M. Doohan 1996  M. Doohan 1997  M. Doohan 1998  M. Doohan 1999  À. Crivillé 2000  K. Roberts Jr. 2001  V. Rossi 2002  V. Rossi 2003  V. Rossi 2004  V. Rossi 2005  V. Rossi 2006  N. Hayden 2007  C. Stoner 2008  V. Rossi 2009  V. Rossi 2010  J. Lorenzo 2011  C. Stoner 2012  J. Lorenzo 2013  M. Márquez 2014  M. Márquez 2015  J. Lorenzo 2016  M. Márquez 2017  M. Márquez 2018  M. Márquez 2019  M. Márquez 2020  J. Mir 2021  F. Quartararo 2022  F. Bagnaia 2023  F. Bagnaia 2024  J. Martín 1949  B. Ruffo 1950  D. Ambrosini 1951  B. Ruffo 1952  E. Lorenzetti 1953  W. Haas 1954  W. Haas 1955  H. Müller 1956  C. Ubbiali 1957  C. Sandford 1958  T. Provini 1959  C. Ubbiali 1960  C. Ubbiali 1961  M. Hailwood 1962  J. Redman 1963  J. Redman 1964  P. Read 1965  P. Read 1966  M. Hailwood 1967  M. Hailwood 1968  P. Read 1969  K. Carruthers 1970  R. Gould 1971  P. Read 1972  J. Saarinen 1973  D. Braun 1974  W. Villa 1975  W. Villa 1976  W. Villa 1977  M. Lega 1978  K. Ballington 1979  K. Ballington 1980  A. Mang 1981  A. Mang 1982  J. Tournadre 1983  C. Lavado 1984  C. Sarron 1985  F. Spencer 1986  C. Lavado 1987  A. Mang 1988  S. Pons 1989  S. Pons 1990  J. Kocinski 1991  L. Cadalora 1992  L. Cadalora 1993  T. Harada 1994  M. Biaggi 1995  M. Biaggi 1996  M. Biaggi 1997  M. Biaggi 1998  L. Capirossi 1999  V. Rossi 2000  O. Jacque 2001  D. Kato 2002  M. Melandri 2003  M. Poggiali 2004  D. Pedrosa 2005  D. Pedrosa 2006  J. Lorenzo 2007  J. Lorenzo 2008  M. Simoncelli 2009  H. Aoyama 2010  T. Elías 2011  S. Bradl 2012  M. Márquez 2013  P. Espargaró 2014  T. Rabat 2015  J. Zarco 2016  J. Zarco 2017  F. Morbidelli 2018  F. Bagnaia 2019  Á. Márquez 2020  E. Bastianini 2021  R. Gardner 2022  A. Fernández 2023  P. Acosta 2024  A. Ogura Giacomo Agostini, Hideo Kanaya, Kenny Roberts, Eddie Lawson, Wayne Rainey, John Kocinski, Luca Cadalora, Norifumi Abe, Max Biaggi, Valentino Rossi, Jorge Lorenzo, Ben Spies, Maverick Viñales, Fabio Quartararo