MH6 Team (2016)

In the last race of the 2016 Moto3 World Championship, Fernández made his Grand Prix debut at Valencia, as the replacement for the injured María Herrera,^[3] scoring championship points with an 11th place.

Aspar Team (2017–2019)

Fernández would make three wild-card round entries for the Mahindra Aspar Team in 2017, finishing 25th in Jerez, retiring in Assen, and finishing 22nd in Germany.

He would once again make four wild-card round entries for the Aspar Team in 2018, this time riding KTM bikes used by the Aspar team. He improved his prior season's results, and earned himself a full time ride for next year with his 10th place in Barcelona, 9th place in Germany, 17th place in Aragón, and 13th place in Valencia.

In his first full year in Moto3, Fernández had a decent rookie season, finishing in the points ten times, finishing in the top-ten six times, with his season's highest being a 5th-place finish in Germany. He ended the 2019 season 21st in the championship standings, with 60 points.

Red Bull KTM Ajo (2020)

Due to his good performances, Fernández was given a contract by the Red Bull KTM Ajo team for the 2020 season, which saw him steadily improve over the course of the year. He had six Pole Positions during the season (Czechia, Austria, Misano, Aragón, Valencia, and Portimao), two 3rd places in Aragón and Valencia, and won the European Grand Prix, and Portuguese Grand Prix.^[4][5] He ended the season 4th in the championship standings, with 159 points, just 15 points away from 1st.

Red Bull KTM Ajo (2021)

Being promoted to Moto2, but staying with the Red Bull KTM Ajo family, Fernández had the best rookie season ever in Moto2, beating several records of Marc Márquez.^[6] He won eight races (Portugal, France, Netherlands, Austria, Aragón, Rimini, USA, and Valencia),^[7] had seven Pole Positions, stood on the podium 12 times, finished outside of the top-seven just the three times he retired from a race (Germany, Great Britain, Misano), and finished second in the standings, just 4 points away from teammate Remy Gardner, who won the title.

Tech3 KTM Factory Racing (2022)

In August 2021, it was announced that both Fernández and Gardner would be promoted to MotoGP, riding for Red Bull KTM Tech3 in the 2022 season.^[8] Fernández becomes just the third rider to be promoted to MotoGP after one lone season in Moto2, following Maverick Viñales, and Joan Mir.

RNF MotoGP Team (2023)

In August 2022, Fernández signed with RNF Racing for 2023, partnering Miguel Oliveira.^[9]

Trackhouse Racing (2024)

Races by year

(key) (Races in bold indicate pole position, races in italics indicate fastest lap)

Races by year

(key) (Races in bold indicate pole position, races in italics indicate fastest lap)

By season

By class

Races by year

(key) (Races in bold indicate pole position, races in italics indicate fastest lap)

* Season still in progress.