Montero made his World Supersport debut in 2021, participating in 13 races that season atop his Yamaha R6. Prior to his WorldSSP debut, the Madrid native had competed in Spanish Superbikes 600 in 2020 and 2021, earning a 4th place finish in 2021. Since his single season appearance in WorldSSP in 2021, he competed in Spanish Superbikes 1000 and Moto2 from 2022 to 2024. A fourth-place finish in 2022 then a fifth-place in 2023 in Spanish Superbikes culminated in his 2024 move to the Moto2™ European Championship where he finished 27th in the Riders’ Championship, and now as a challenge rider in 2025 as a part of D34G WorldSSP Racing Team.