Lecuona made his Moto2 World Championship debut in 2016 as a replacement for the injured Dominique Aegerter at CarXpert Interwetten, later becoming the permanent substitute that season. In 2017 he missed the opening rounds due to back and collarbone injuries sustained in pre-season testing at Jerez, managed his first points at world championship level in Malaysia, and finished thirty-fifth in the standings.
His Moto2 results improved steadily. At the 2018 Valencian Community Grand Prix, the final race of the season, Lecuona took his first world championship podium with second place behind fellow KTM rider Miguel Oliveira. That year he placed twelfth in the championship with six top-ten finishes. In 2019 he added a second podium, finishing third at the Thailand Grand Prix behind Brad Binder and Luca Marini.
Lecuona's first MotoGP appearance came at the 2019 season finale in Valencia, where he deputised for Miguel Oliveira before his scheduled debut the following year. He was signed by Tech3 KTM for 2020 after the departure of Johann Zarco created a cascade of team movements.
In 2020, Lecuona scored points in seven rounds, including three top-ten finishes — ninth in Aragón and Austria, and tenth in Styria. He missed three late-season rounds after his brother and personal assistant tested positive for COVID-19, placing him in mandatory quarantine in Andorra, and he subsequently tested positive himself before the Valencian Grand Prix.
He remained with Tech3 for 2021 alongside Danilo Petrucci. Both riders lost their seats after the Moto2 championship dominance of Remy Gardner and Raúl Fernández led to the pair being signed by Tech3 for 2022, leaving Lecuona without a MotoGP ride.
Following his departure from MotoGP, Lecuona secured a place in Honda's factory Superbike effort for the 2022 Superbike World Championship, replacing the departing Álvaro Bautista. He spent four seasons with Honda Racing Corporation aboard the CBR1000RR-R, representing a sustained attempt by Honda to rebuild its WorldSBK competitiveness.
Lecuona made several appearances as a replacement rider back in MotoGP during 2023. He substituted for Marc Márquez at the Spanish Grand Prix and for Joan Mir at the Dutch TT, both with the Repsol Honda Team. He also covered for Álex Rins at multiple rounds — the British, Austrian, Catalan, Malaysian, and Qatar Grands Prix — with the LCR Honda Castrol team. In 2026 he substituted for Álex Márquez at the Hungarian Grand Prix with the BK8 Gresini Racing MotoGP team.
For the 2026 WorldSBK season, Lecuona joined Aruba.it Racing — Ducati to replace the departing Álvaro Bautista, the same rider he had replaced at Honda four years earlier. The appointment to the top Ducati factory squad marked the most significant team opportunity of his career.
Lecuona's career illustrates the porous boundary between MotoGP and WorldSBK at the highest level. He arrived in WorldSBK via MotoGP rather than traditional superbike pathways, and his ability to return to the premier class as a credible replacement rider across multiple teams speaks to his continued standing. The move to the Ducati factory team in 2026 positions him among WorldSBK's frontline contenders for the first time.