Jeferson Guaresi was born on June 1, 1998, in Rolim de Moura, Rondônia, Brazil. In his youth, he excelled as a football (soccer) goalkeeper, competing successfully at the state level. Despite being shorter than typical goalkeepers, his exceptional athleticism and disciplined work ethic significantly contributed to his team's regional achievements. At age 11, influenced by friends training at Rafael Godoi's academy, Guaresi began practicing Brazilian Jiu-Jitsu, marking the start of his grappling journey.

Under the mentorship of his first instructor, Rafael Godoi, Jeferson quickly demonstrated remarkable potential in Brazilian Jiu-Jitsu. Godoi played a crucial role in cultivating Guaresi's competitive mindset, particularly after a disappointing performance at the 2015 Brazilian Nationals (CBJJ). Recognizing Jeferson's dedication and talent, Godoi introduced him to renowned instructor Cicero Costha, setting the stage for a pivotal turning point in his career.

Training at PSLPB

In 2015, Guaresi relocated to São Paulo to train full-time at PSLPB, Cicero Costha's prestigious academy known for producing elite competitors. After two years of rigorous training and competition, he earned his brown belt directly from Costha.

Transition to Unity Jiu-Jitsu

During his time at PSLPB, Guaresi began visiting Unity Jiu-Jitsu in New York City, an academy closely affiliated with PSLPB. In mid-2019, he received his black belt jointly from Cicero Costha and Murilo Santana. Notably, Guaresi began teaching at Unity Jiu-Jitsu as early as his purple belt days, eventually becoming a full-time head instructor at the academy.

Expanding his influence within the grappling community, Jeferson Guaresi founded Sintonia Jiu-Jitsu academy in New York City. While managing his own academy, he continues to represent Unity Jiu-Jitsu in competitions. At Sintonia, Guaresi emphasizes a balanced approach, integrating traditional positional pressure with contemporary guard passing techniques, mirroring his personal competitive style.

Guaresi has notably excelled in no-gi competitions, capturing prestigious titles and solidifying his reputation as a top competitor. He won the IBJJF No-Gi World Championship in 2021 in the featherweight division and secured two IBJJF No-Gi Pan American Championships (2019 and 2021). Additionally, he claimed victory at an ADCC Open tournament in 2022 and earned runner-up honors at the 2019 ADCC São Paulo Trials as a purple belt, further highlighting his prowess in no-gi grappling.

Jeferson Guaresi is recognized for his distinctive blend of classic positional pressure and modern guard passing techniques. His competition style emphasizes strategic guard passing, positional dominance, and dynamic athleticism. By seamlessly integrating traditional fundamentals with contemporary competitive strategies, Guaresi has established himself as a versatile and formidable presence on the international Brazilian Jiu-Jitsu circuit.