Both of his legs were amputated. Prior to that he was heavily involved in kart racing all over the UK and the Channel Islands, and then a successful Ginetta Junior racer.
After treatment and therapy, Monger returned to competition in November 2017. In 2018, Monger was awarded the BBC Sports Personality of the Year Helen Rollason Award for outstanding achievement in the face of adversity. In 2019, he will combine his yet to be announced racing season with analysis for Channel 4's F1 coverage.
In June 2018 Monger drove a Formula 1 racing car for the first time when he tested a Sauber C30 built by Tour-De-Force Power Engineering for Heritage F1 at the Rockingham Motor Speedway in Corby. The car had been specially converted to match the hand controls present in the Carlin BRDC British Formula 3 car he races.
A documentary feature about Monger's first Formula 1 drive was shown as part of Sky F1s coverage of the 2018 Austrian Grand Prix. Another documentary about Monger's career, Driven: The Billy Monger Story, was produced by the BBC and released via BBC Three in November 2018.