When he made his Formula One debut at the 2009 Hungarian Grand Prix in Budapest, the 19-year-old Spaniard became the youngest GP starter of all time. He had been promoted from the Red Bull Junior Programme only a few weeks earlier to become the test and reserve driver for Toro Rosso and Red Bull.

Like so much other young talent, the Barcelona-born newcomer´s motorsport career began in karting. He was accepted into the Red Bull Junior Team in 2005 and, in addition to karting, he also gained his first experience in formula racing, competing in Formula Junior 1.6 in Italy. With two victories under his belt, he finished third in the championship.

One year later, Alguersuari stormed his way through three Renault Championships at once. He claimed three victories in the Formula Renault 2.0 Winter Series, won Rookie of the Year in the Italian Formula Renault 2.0 and came 12th in the Eurocup Formula Renault 2.0. In 2007, he stayed with Formula Renault 2.0 in Europe and Italy, and ended the season runner-up in Italy with three victories.

His greatest success to date was in the 2008 British Formula Three season, where he won the title after five wins, six pole positions, twelve podium finishes and five fastest laps. In the same year, he also achieved success three times in the Spanish F3 Championship. Alguersuari started the 2009 season driving for the Carlin Team in the Formula Renault 3.5 World Series. In the middle of the 2009 season he was promoted to Formula One and the Toro Rosso team, where he replaced Sebastien Bourdais.