As a privateer he achieved notable results on a 450 in 2023 and the following season he was picked up by the factory Monster Energy Pro Circuit Kawasaki team for the 2024 AMA National Motocross Championship.
Jake Masterpool has also raced professional motocross in the United States, whilst the eldest brother Jesse lost his life due to injuries sustained in a crash in 2010.
[6] At the age of 17, Masterpool made his professional debut with the Monster Energy Yamalube Star Yamaha Racing in the 250 class of the 2019 AMA National Motocross Championship.
Competing in the 250SX West class, he finished eighteenth in the final standings after missing the last two rounds due to tweaking his ankle whilst training.
After missing the entire supercross season due to a wrist injury, Masterpool competed in five rounds of the 2022 AMA National Motocross Championship before breaking his kneecap in a crash.
[citation needed] Staying on a 450, Masterpool competed in the 2024 AMA Supercross Championship for the HBI Kawasaki team but missed the first six rounds due to recovering from an Appendectomy.
With injuries for Cameron McAdoo and Seth Hammaker, the factory Monster Energy Pro Circuit Kawasaki team signed Masterpool to ride in the 250 class as a fill-in.
[15] A further race win in the opening moto at the sixth round saw him pick up second overall, with additional top-ten finishes throughout the rest of the season resulting in fifth in the final standings.