Hartley was born in a family well integrated within motorsport. His father, Bryan, had raced in many forms of motorsport, most notably Formula Atlantic. At the age of six, Hartley began his motor racing career in kart racing. After a first season in single-seater, Hartley moved to Europe, competing in the Eurocup Formula Renault 2.0 and Formula Renault 2.0 Northern European Cup (NEC) and took championship title in the Eurocup.
After F3, he came back in World Series by Renault with Tech 1 Racing to compete in Formula Renault 3.5 Series and was appointed as official reserve driver for both the Red Bull Racing and Scuderia Toro Rosso F1 teams. He continued in Formula Renault 3.5 Series with Gravity-Charouz and was test driver with AMG Mercedes F1 Team. In 2012, he started in Endurance racing and cliched 2nd position in Le Mans in 2015.
The World Series by Renault team wishes him a very happy birthday.