2021

The Frenchman made his debut at the Formula Regional level in 2021, competing in the first three rounds of the F3 Asian Championship with Evans GP.^[6] He impressed right from the start, scoring a myriad of podium finishes, which included three podiums in the second round at Yas Marina. Despite not taking part in the latter rounds of the campaign, Hadjar managed to finish sixth in the standings, highest of all part-time entrants.

Hadjar's main campaign would lie in the Formula Regional European Championship, where he partnered Zane Maloney, Léna Bühler and fellow countryman Hadrien David at R-ace GP.^[7] The Frenchman scored his first points, along with his first rookie win, at the first round in Imola.^[8] He then proceeded to score his first podium at the next event, held in Barcelona, and achieved his first Formula Regional victory in the first race on the streets of Monaco.^[9] At that same weekend Hadjar finished second in race two, only behind teammate Maloney, and closed in on the championship lead held by Grégoire Saucy.^[10] However, Hadjar would be unable to score a podium finish until the final round of the season, despite amassing a number of finishes in the top six. Following a disappointing round at Mugello where he hadn't scored any points the Frenchman bounced back with a double podium in that final round at Monza, scoring a win in the second race after the leading pair collided.^[11] Hadjar ended up fifth in the standings, just four points behind teammate Maloney, and won the honours for the best rookie of the season.

2022

At the start of 2022, Hadjar raced in the Formula Regional Asian Championship with Hitech Grand Prix.^[12]

2023

Hadjar was invited to test for Hitech Grand Prix at the 2022 F2 post-season test in Yas Marina.^[17] In January 2023, Hadjar was announced to be progressing into the 2023 Formula 2 Championship, continuing his relationship with Hitech alongside Jak Crawford.^[18]

Hadjar qualified 14th in Bahrain.^[19] Hadjar finished the sprint race in 20th after struggling with his tyres ^[20] but he finished 7th in the feature race after a good drive securing his first points in formula 2. ^[21] Hadjar followed this weekend up by qualifying 19th for the race in Saudi Arabia.^[22] Hadjar would move up the field to finish the sprint in 12th.^[23] The feature race would be even better as Hadjar would finish 9th scoring two points. ^[24]

Hadjar qualified 4th at Formula 2's first visit Albert Park^[25] but was given a grid penalty for impeding dropping him to 7th. Hadjar would finish the sprint race in 6th.^[26] The feature race however would be disastrous as Hadjar would finish 15th after contact with former F3 rival Oliver Bearman during a pit stop would leave him with a broken front wing and a penalty.^[27].Hadjar qualified 18th in Baku.^[28] Hadjar would survive the chaos at the end of the race to finish 8th.^[29] but he was demoted to 11th for illegaly overtaking Jack Doohan during the safety car restart. Hadjar would bounce back by finishing 7th in the feature race after trying an alternative strategy^[30]

Hadjar qualified 10th in Monaco meaning he would start the sprint from pole.^[31] Hadjar led into turn 1 and held the lead until lap 6 when a mechanical failure ended his race cruelly denying him his first win.^[32] Hadjar would finish the feature race 12th ending what was a miserable weekend for the frenchman.^[33] Hadjar qualified 20th for the Spain weekend^[34] and finished the sprint race in 12th.^[35] The Feature race wouldn't be much better as Hadjar finished 20th marking another miserable weekend for him.^[36]

Hadjar qualified 21st in Austria.^[37] For the sprint race Hadjar gambled by starting on slicks on a drying track, which paid off as he moved from 21st to fourth by the chequered flag just missing out on the podium.^[38], However Clement Novalak would be disqualified for tyre pressure infringements promoting Hadjar to third which marked his first podium in F2.^[39], The feature race wouldn't be as successful as Hadjar would finish 12th just missing out on points.^[40]

Hadjar qualified 9th at Silverstone.^[41], Starting the sprint in P2 Hadjar would fight all race for a podium but would finish in 5th place.^[42] The feature race however would be a disaster as a poor strategy choice would lead to a 15th place finish.^[43] Hadjar qualified 5th in Hungary.^[44] In the sprint Hadjar would hold off championship leader Frederik Vesti to finish 8th,^[45] whilst the feature race would lead to a 5th place finish.^[46],which marked the first time Hadjar scored points in both races during the season.

Hadjar qualified 13th Spa.^[47] Hadjar would finish the sprint 11th.^[48] The feature race however would end in disaster as Hadjar retired by crashing into the pit exit wall which broke his front wing ending his chance for points.^[49]

Hadjar qualified 9th at Zandvoort.^[50] When sprint pole sitter Theo Pourchaire failed to start the sprint, Hadjar started at the front and led into the first corner but then the race was stopped after his teammate Jak Crawford and the two Campos drivers of Kush Maini and Ralph Boschung had a huge accident into turn 4. The sprint was then abandoned after the rain didn't clear up and with Hadjar in first place the stewards awarded him his first win in the championship(but he was awarded no points as less then two racing laps had been completed).^[51] Hadjar finished the feature race in 6th after benefitting from the championships top 6 drivers all having bad races.^[52]

Hadjar qualified an impressive 4th for the Monza race.^[53] Hadjar finished the sprint 6th but he would slip back to 11th following a penalty for leaving the track and gaining an advantage.^[54] The feature race would be the same as Hadjar finished 11th ending a frustrating weekend for the Frenchman.^[55] Hadjar qualified 8th for the season finale in Yas Marina.^[56] Hadjar got a good start in the sprint and ran second for a few laps until Frederik Vesti passed him dropping him to third. Hadjar would then be passed by Richard Verschoor ending his chance of a podium before he was overtaken by Dennis Hauger on the last lap meaning he finished the sprint 5th.^[57] For the feature race Hadjar finished 8th after running on the normal strategy ending a frustrating and disappointing season with his second double points finish of 2023.^[58]

Hadjar finished 2023 a disappointing 14th in the drivers championship with 55 points(two points behind Hitech teammate Jak Crawford) with his third place finish in the Austria sprint race being his best result of the season. Hadjar also helped Hitech Pulse-Eight finish 8th in the team's championship. Hadjar drove for Campos Racing in the post season test at Abu Dhabi ending the final day with the fastest time.

2024

Hadjar switched to Campos Racing for the 2024 Formula 2 season, teaming up with fellow Red Bull junior Pepe Martí.^[59]

Hadjar qualified 2nd for the opening race of the season in Sakhir.^[60] Hadjar finished the sprint race in 4th.^[61] The feature race however would end in disaster as Hadjar was spun around by Gabriel Bortoleto into the first corner before being collected by Enzo Fittipaldi ending his race.^[62]

Hadjar qualified 8th in Jeddah.^[63], The sprint however would end in disaster as Hadjar would be forced to retire on the penultimate lap with an engine issue whilst running 9th.^[64], The feature race wouldn't go any better as Hadjar was forced to retire with another issue whilst running 7th ending what was a miserable weekend for the Frenchman.

Hadjar qualified 8th for the round in Australia.^[65] At the start Hadjar tried to pass Roman Staněk but he wedged his teammate Pepe Marti into Invicta Racing's Gabriel Bortoleto and whilst he continued and took the lead into the first corner, Marti and Bortoleto were out of the race. Hadjar then dominated the sprint after another safety car to win his first race in F2.^[66] However Hadjar was judged to have caused the incident with his teammate and Bortoleto so he was given a 10 second time penalty dropping him to 6th place.^[67]

Hadjar ran 8th at the start of the feature race but pitted under a safety car from Dennis Hauger's crash which allowed him to come out ahead of Andrea Kimi Antonelli in 7th. Hadjar then passed Taylor Barnard, Enzo Fittipaldi and Roman Stanek to move into third place before Jak Crawford and Kush Maini pitted handing Hadjar the lead. He would then hold off Paul Aron to win the feature race and this time it counted which marked Hadjar's first win in Formula 2.^[68] Hadjar left Melbourne sitting 4th in the championship on 34 points, 28 points behind leader Zane Maloney.