Vierge finished as runner-up in the 2015 FIM CEV Moto2 European Championship and made his debut in the Moto2 World Championship that same year, competing with the Tech 3 Team from round ten onwards. He remained with that squad as a permanent rider for the following two years, ending the 2016 season as Rookie of the Year and achieving his first podium in 2017 (Japan) during a strong season in which he regularly battled at the front.

Two more podium finishes (Argentina and Australia) resulted from his collaboration with the Dynavolt Intact GP team in 2018, while over the last three years, first as teammate to Alex Marquez in the EG 0,0 Marc VDS garage, and most recently with Petronas Sprinta Racing, he has been a regular Moto2 top-ten finisher (ten times in 2021) and scored another podium (3rd) this year at Catalunya, ending the season in 11th position overall.

In 2022 Vierge joined the WorldSBK Championship as factory Honda rider in the Team HRC.

After securing a seventh-place finish in his first race at Aragón, Vierge proved to be a regular top ten finisher in the subsequent races. His best result of the season was a close fourth-place finish in the Superpole race at Misano, the Spaniard rounding out the year in tenth place overall. After a strong rookie campaign, Vierge will be looking for podium finishes in 2023.

In 2023 Xavi achieved his first WorldSBK podium at Mandalika and consistently fought in the top ten, ending his 2023 WorldSBK campaign in 10th place overall. Following in his teammate’s footsteps, he took part in the 2023 edition of the prestigious Suzuka 8 Hours race, riding for the Honda factory team Team HRC with Japan Post alongside Takumi Takahashi and Tetsuta Nagashima. The team won the race, scoring a second consecutive victory for Honda, its 29th overall.

On occasion of the last Round of the year Honda Racing Corporation announced a contract extension with both Xavi Vierge and Iker Lecuona and for the next two years (2024-2025).