Callum started karting in 2008 at the age of 10 and in 2011, he won Formula Kart Stars and finished 3rd in German Junior Karting Championship. In 2013, he won the WSK Masters Series and the WSK Final Cup and also coming runner up in the WSK Euro Series and CIK-FIA World Cup. In 2013, Callum drove in KF2 and KF machinery. His last year in karting (2014) ended up with 4th in CIK-FIA World Championship, 3rd in third in the WSK Champions Cup and 1st in WSK Super Masters Series and the CIK-FIA European Championship.
Callum Ilott made his single-seater debut with ETEC Motorsport in Toyota Racing Series during the 2015 season. He finished 16th in the championship. During this season, he was also confirmed as a Red Bull Junior driver.
He stepped up to Formula 3 in 2015 with Carlin Motorsport. He also tested F3 cars and Formula Renault 2.0 to gain some experience before making his Formula 3 debut. Callum finished 7th in rookie championship and 12th in the overall championship. The following year, he raced with Van Amersfoort Racing and finished 6th. For the 2017 season, he moved to Prema Racing where he competed alongside Guanyu Zhou and Maximilian Günther. He ended up finishing 4th in that season. Also in 2017, he was added to the Ferrari Driver Academy.
Callum also competed in Macau Grand Prix during his racing in Formula 3. He raced with Carlin on his debut for Macau Grand Prix with a DNF. The following year, he drove with Van Amsfoort and gained a 5th position. In 2017, Callum won the qualifying race and came 15th in the main race.
He did GP3 testing with ART Grand Prix and competed with them for the following season in 2018. He finished 3rd in the championship behind the champion being Anthoine Hubert and Nikita Mazepin, both his teammate in ART.
During the season in GP3, he again competed in Macau Grand Prix. He finished 3rd in the qualifying race and 7th in the main race after Jüri Vips was penalised for passing under a red flag.
FIA Formula 2 Championship
Callum initially made his debut with Trident in the 2017 season, competing at Silverstone’s feature race and sprint race after replacing Johnny Cecotto Jr.
He made his proper debut in the Formula 2 championship with Charouz alongside Juan Manuel Correa for the 2019 season. He gained a pole position in Monza after a raining session. Callum’s highest position was 3rd in Barcelona’s sprint race and Sochi’s sprint race. He finished 11th in the championship with 74 points behind Anthoine Hubert.
In the 2019 Macau Grand Prix, he raced with Charouz. In the qualifying race, he got 5th and in the main race, he classified as 6th.
Callum moved to UNI-Virtuosi for the 2020 season alongside Guanyu Zhou.