Carlos Sainz begins his career in karting in 2006, when he obtained a third position in the Industrie de Minikarts Tournament. With only 14 years old, he wins the Asia-Pacific title KF3 and is runner-up in the Spanish KF3 championship. After winning the Monaco Kart Cup Junior in 2009 and being runner-up in the KF3 European Championship, he becomes part of the Red Bull young drivers program. At the age of 15, he jumps into Formula BMW Europe and wins the rookie trophy of the year. In 2011, he achieved the second place in the Eurocup of Formula Renault 2.0.
In 2013 he starts his career in F1, participating in the tests of young drivers, where he made the second best time. In 2015 his moment comes with the Scuderia Toro Rosso where he becomes official driver. That year he becomes the Spanish rider that starts on top of the grid in his debut. In 2016 he improves the positions of the previous season by scoring in 9 of the first 11 races.
In 2017 he signs for Renault for the season and the Madrilean rider finishes in ninth position, ahead of all the drivers with whom he shared a team.