He spent a year and a half as part of the GB Elite set-up in Sheffield and boxed for England around a dozen times, competing at the European Youth championships twice and winning gold medals at multi-nations in Tammer (Finland) and Brandenburg (Germany).

[7] In his fourth fight, he knocked out Mauricio Barragan, a late substitute, in the second round to win the vacant WBC Youth heavyweight title.

[10][11] He won the English heavyweight title in his eighth fight in June 2018, beating journeyman Tom Little by stoppage in the fifth round.

[6][17] Boxing journalist Steve Bunce said he "...fought like an old, seasoned bruiser, his feet flawless, his jab a stiff weapon inherited from relics of the ring".

The first round would end up being the last that Snijders would survive, as the referee waved the fight off after Dubois dropped his opponent for the fourth time.

On 6 October, Warren announced the fight would take place on BT Sports, without pay-per-view, which was considered a huge reversal, on 28 November at Church House in London.

[41] Only two days before the fight, Joyce team hit a setback as trainer Salas tested positive for Covid upon arriving at the hotel in London.

[44][45] In a closely contested fight that had implications for future world title hopes, Dubois was landing the harder and cleaner punches while Joyce stayed at range behind powerful jabs.

The repeated accurate jabs from Joyce caused swelling to the left eye of Dubois from the second round.

In the tenth, after another hard jab landed on his now-swollen-shut eye, Dubois went down on one knee, allowing the referee to count him out to suffer the first loss of his career.

[50] Dubois was hit with claims that he quit from fellow boxers and pundits, however was also backed by some, saying it was the right decision and potentially saved his career.

[51][52][53][54][55][56] Following the fight it was revealed that Dubois had suffered a broken left orbital bone and nerve damage around the eye and would be out of action for around six months.

[62] Following his first professional defeat, Dubois split with trainer Martin Bowers and hired Mark Tibbs in February 2021.

[65] Dubois won the bout by second-round knockout, winning the vacant WBA interim heavyweight title in the process.

The win also made him the mandatory challenger for the WBA (Regular) title held by undefeated Trevor Bryan.

He along with Tommy Fury would appear on the undercard of Jake Paul vs. Tyron Woodley on 29 August at Rocket Mortgage FieldHouse in Cleveland, Ohio.

[72] In the meantime, previous WBA (Regular) belt holder Mahmoud Charr filed a lawsuit against Bryan's promoter Don King.

Trainer Shane McGuigan said they would like to make a defence of the title in London and mentioned Dillian Whyte as a potential opponent.

On 20 October, a press release was put out which announced Dubois would make the first defence of his WBA (Regular) heavyweight title against Kevin Lerena (28-1, 14 KOs) on 3 December, at the Tottenham Hotspur Stadium in London, England on the undercard of Tyson Fury vs. Derek Chisora III.

[94] A few months later, reports confirmed that Dubois had split with trainer Shane McGuigan and partnered with Don Charles ahead of the potential world title fight with Oleksandr Usyk in the Summer of 2023.

[99] The fight took place on 26 August at the Stadion Wroclaw in Wrocław, Poland for Usyk's WBA (Super), IBF, WBO, IBO and The Ring titles.

[104] Debate followed regarding the fifth round, many observers believed the low blow was a legal punch and thus potentially resulted in a KO victory for Dubois.

[105][106][107] In November 2023, Riyadh Season announced a blockbuster card which would take place on on December 23, 2023 with Anthony Joshua vs. Otto Wallin as the headline.

[109] Dubois put on a show and likely the most entertaining victory on the card, stopping Miller in the tenth round.

[114] On 15 April 2024 at a press conference, it was confirmed that Dubois would face IBF top ranked contender Filip Hrgović in Riyadh on 1 June, co-featuring on a card that was headlined by a bout between fellow heavyweights Zhilei Zhang and Deontay Wilder.

[117] Hrgović went into the bout with high confidence expecting a stoppage win, citing that Dubois had suffered two previous losses, where he had to rebuild his career.

[119] In what was considered his biggest win to date, Dubois defeated Hrgović via eighth-round TKO, doctor's stoppage due to cuts.

[124] It was announced that he would be making his first defence of the title against former two-time unified champion Anthony Joshua at Wembley Stadium in London on 21 September.

Hearn stated Joshua would wait for the outcome of the heavyweight rematch between Oleksandr Usyk vs. Tyson Fury before making his next move.

This opened up a list of potential opponents for Dubois, including the likes of Fabio Wardley, Zhilei Zhang, Joseph Parker, Agit Kabayel and Martin Bakole amongst the contenders.