He won his first ITF Grade 1 in Canada at the Repentigny Internationaux de Tennis Junior, defeating Félix Auger-Aliassime in the semifinal, and Liam Caruana in the final.

In October, he won his first doubles title in a Futures tournament held in Nigeria partnering French player Alexis Klégou.

During 2017, as a junior, he made his ATP debut at the Barcelona Open Banc Sabadell in April thanks to a qualifying wild card.

He defeated Rudolf Molleker in the first round and won the 2017 Wimbledon boys' singles title without dropping a set, winning the final against Argentine Axel Geller.

In 2018, he was the hitting partner for the Spanish Davis Cup team at the tie Spain vs. Great Britain held at Marbella.

In March, Davidovich won his first ITF Futures 15K title at Quinta do Lago in Portugal, defeating Roberto Ortega Olmedo.

Davidovich Fokina started the season playing the first round of Australian Open qualifying by defeating Daniel Gimeno Traver.

Later in the month, he reached the semifinals of the 2019 Estoril Open as a qualifier, beating Gaël Monfils and Taylor Fritz along the way.

He won his first ATP title in doubles at the 2020 Chile Open in Santiago, partnering with fellow Spaniard Roberto Carballés Baena, where they defeated 2nd seeded pair Marcelo Arévalo/Jonny O'Mara in the final.

He reached the second round of the 2020 French Open for the first time by defeating wildcard Harold Mayot before losing to 13th seed Andrey Rublev.

At the 2020 US Open, Davidovich Fokina reached the fourth round of a Grand Slam for the first time in his career, beating Dennis Novak, Hubert Hurkacz, and Cameron Norrie, before losing in straight sets to Alexander Zverev.

[21] He retired after losing the first set during his quarterfinals match against fourth seed Stefanos Tsitsipas due to a left quadriceps injury.

[26] Getting past qualifying at the Italian Open, he reached the third round where he was beaten by top seed and five-time champion, Novak Djokovic.

[27] Ranked 46 at the French Open, he stunned 15th seed Casper Ruud in his third-round match to reach his second fourth round Grand Slam appearance.

[30] Seeded sixth at the Eastbourne International, Davidovich Fokina retired after losing the first set during his second-round match against Vasek Pospisil due to a lower back injury.

[32] Representing Spain at the Summer Olympics, Davidovich Fokina lost in the third round to top seed Novak Djokovic.

[38] At the 2023 BNP Paribas Open he reached the quarterfinals of a Masters 1000 for a third time in his career defeating wildcard Yibing Wu, 13th seed Karen Khachanov and qualifier Cristian Garín.

[4][3][42] He fell out of the top 50 on 12 August 2024, following the 2024 National Bank Open where he defeated third seed Daniil Medvedev in the second round but retired in the third against eventual semifinalist Matteo Arnaldi and failed to defend his semifinal points from the previous season.

Davidovich Fokina returned to form by winning two five set matches, defeating Félix Auger-Aliassime and Jakub Mensik to enter the fourth round of the 2025 Australian Open (AO) for the first time.

Additionally, Davidovich Fokina can often be seen diving on courts of all surfaces, which leads to both wildly entertaining shotmaking and occasionally injury.