Born in Paris in 2004, Isack's motorsport career began in karting in 2012, where he proved himself to be a natural talent in various national championships. In 2019, at 14-years-old, Isack made his single-seater debut in the French Formula Four Championship, winning at Spa-Francorchamps and finishing 7th in the standings.

For his second year in the series in 2020, he scored three wins, eleven podiums, and two pole positions, finishing 3rd in the championship. During 2021, Isack competed in both the Formula Three Asian Championship and Formula Regional European Championship. Isack finished 6th in the F3 Asian series with Evans GP, whilst simultaneously racing in the Formula Regional European Championship with R-ace GP, impressing in Monaco by winning the race for his first visit in the principality.

In 2022, Isack graduated to FIA Formula Three with Hitech Grand Prix and into Formula Two the following year. The 2024 season marked a pivotal year in Isack’s career as he joined Campos Racing for his second season in F2. Key podiums in Monaco, Belgium, Silverstone, and Qatar were standout moments of a season that solidified his place as one of the most promising drivers.

In 2023, he made his Formula One debut in free practice during the Mexico City Grand Prix with Scuderia AlphaTauri. In 2024, Isack was promoted to reserve driver for both Red Bull Racing and Visa Cash App RB, and in December 2024 Isack secured himself a full time F1 seat with Visa Cash App Racing Bulls, where he will be partnering with Yuki Tsunoda in 2025.