Dennis joined the then-BMW i Andretti Motorsport, now Avalanche Andretti Formula E outfit, after earning the prized factory seat with an impressive performance in the marque's driver selection evaluation ahead of the 2020/21 season.
Born in Nuneaton, Warwickshire, Dennis entered the motorsport world in 2007 with a successful start winning multiple British and World karting championships.
Following this, Dennis made the step up into single-seaters in 2011. He quickly got up to speed with a dominant performance in the inaugural InterSteps Championship, taking the title with eight wins, seven poles and 16 podiums.
The Brit continued this championship-winning progress in 2012, claiming the Formula Renault Northern European Cup on his first attempt. This performance was enough to earn him the prestigious McLaren Autosport BRDC Award - a top accolade in British motorsport that ranks fellow Formula E drivers Oliver Turvey, Alexander Sims, Oliver Rowland and commentator Dario Franchitti amongst its winners.
The next season saw Dennis continue in the Eurocup Formula Renault 2.0. His best finish in 2013 was in the non-championship Pau Trophy, where he placed third around the fast but technical Pau road circuit in France.
Dennis continued up the single-seater ladder with a move up to FIA Formula 3 European Championship. After a bedding-in season in 2014, the following year saw the Brit finish third place overall behind Felix Rosenqvist and Antonio Giovinazzi in the highly-competitive series, claiming six wins, six pole positions and 16 podiums. He also claimed a top ten finish at the famous Macau Grand Prix.
For 2016 Dennis competed in the GP3 Series, and victories at Monza and Sepang would net him fourth overall in his debut season. That year also saw Dennis' first experiences in sportscars, driving for G-Drive in the FIA World Endurance Championship which included an appearance for the team in the legendary 24 Hours of Le Mans.
For 2017 and 2018, Dennis displayed his adaptability by racing across a variety of motorsport disciplines, jumping from single-seater in Formula 3 to sportscars in the Blancpain GT Series and the ADAC GT Masters.
Demonstrating his ability in the GT ranks gained Dennis a seat with Aston Martin for their DTM campaign in 2019. In the same year, he also stormed to pole position in the famed Bathurst 12 Hours and finished second in the gruelling endurance race.
Since 2018, Dennis has fulfilled test and development duties for Aston Martin Red Bull Racing. With no major racing action for Dennis in 2020 due to the coronavirus pandemic, this role kept him busy as he conducted on-track and simulator tests for the Formula 1 team.
Despite limited races under his belt in 2020, Dennis was invited to test with BMW's Formula E outfit. After impressing through a series of trials against other more experienced drivers, the 25-year-old was chosen to join Maximilian Guenther for the 2020/21 season in what is the youngest line-up on the grid.
Dennis was undoubtedly one of the season's star drivers, outshining another young hotshot in teammate Maximilian Guenther with a victory in Valencia - where the Brit managed his energy beyond all expectations to win from the front - and another on home soil in London. A technical glitch unceremoniously brought his title charge to an end in the final round. Without that, he could well have pipped Nyck de Vries to top spot. Third was mighty impressive nonetheless, with one of the most successful rookie seasons to date.
After an impressive debut campaign, Dennis arrived into Season 8 with high expectations and a title challenge clear in his mind. The year got off to a good start with third in Diriyah, but a lull followed until an arrival at home saw the Brit charged by the home fans with two visits to the podium in London, including a win. He took this momentum to the finale in Seoul with another podium to wrap up the season.