Born on May 26, 2000, in Manés, Brazil, Samuel Nagai made a significant transition to Japan alongside his family at a young age. The challenges his family navigated during that period proved pivotal — those circumstances guided both Samuel and his brother Jackson Nagai toward Brazilian Jiu-Jitsu. In Japan, Samuel began training under Emerson Noriaki, whose instruction laid the technical and philosophical foundation for what would become a decorated competitive career.

Growing up between Brazilian roots and a Japanese upbringing gave Nagai a distinctive perspective on the sport. That dual cultural experience instilled a discipline and resilience that set him apart as he progressed through the ranks, shaping not only his competitive mindset but also the methodical approach he would carry into elite-level grappling.

Coaches and Mentors

Nagai's technical evolution reflected the influence of a carefully assembled coaching network. Beyond Emerson Noriaki's early guidance, his game was further developed under the tutelage of his brother Jackson Nagai, Marcos Souza, Carlos Holanda, and Lucas Leite. Each mentor contributed distinct dimensions to his game, producing a well-rounded competitor capable of performing at the highest levels across multiple formats.

Colored Belt Career

Nagai's competitive results at the colored belt levels signaled elite potential early on. In 2017, he claimed the IBJJF World Championship Juvenile title, announcing himself as one of the most promising grapplers of his generation. That same year and into 2018, he collected back-to-back FJJA Amazonas State titles at blue belt, reinforcing his dominance on the regional circuit.

The defining achievement of his colored belt career came at the 2018 IBJJF World Championship, where Nagai defeated top competitors of his generation to claim the purple belt gold medal — a landmark result for a teenager still ascending through the ranks.

Brown Belt and Black Belt Promotion

At brown belt in 2020, Nagai demonstrated versatility across weight classes, capturing Fight 2 Win titles at both 155 lbs and 170 lbs. That same year, he reached the podium at the IBJJF Pan Championship, finishing in 3rd place. In August 2020, Nagai received his black belt promotion from Keiser Girão at just 20 years old — the culmination of his formative years in the sport and the launch of his career at its highest level. He competes at black belt as a member of Checkmat.

Establishing Contender Status

Nagai competes in the Leve division at 76 kg / 168 lbs, and his black belt career has been defined by consistent, high-stakes performances at the IBJJF World Championship. In 2022, he reached the podium, finishing in 3rd place and establishing himself as a legitimate threat in one of the sport's most competitive divisions.

Claiming the Title

At the 2023 IBJJF World Championship, Nagai claimed the gold medal — the pinnacle achievement of his black belt career to date. His trajectory from purple belt World Champion in 2018 to the top of the black belt podium in 2023 reflects a competitor who has developed with remarkable consistency across multiple championship cycles.

Across those years, Nagai has built a reputation as one of the most dependable and respected competitors in the Leve division, fulfilling the promise he first displayed as a juvenile champion and cementing his legacy as a complete, championship-caliber grappler.