Guilherme Lambertucci was born on July 2, 1997, in Belo Horizonte, the capital city of Minas Gerais in southeastern Brazil. A naturally large child, he was enrolled in judo at age six — initially for physical conditioning, not competitive ambition. That practical motivation quickly gave way to genuine passion, and young Lambertucci began competing extensively in youth divisions, eventually capturing the Mineiro title, the Minas Gerais State Championship.

His judo career came to an abrupt halt in 2010 when a family relocation placed him far from any available instruction. At twelve years old, Lambertucci sought a new martial discipline and found it at the Magrelo Fight Academy in Belo Horizonte, where coach Fábio Costa introduced him to Brazilian Jiu-Jitsu. That first encounter with the sport proved transformative, launching a five-year foundational period that would shape the competitor he was destined to become.

Lambertucci's five years under Fábio Costa at the Magrelo Fight Academy provided the technical foundation that allowed him to thrive at higher levels of competition. Upon reaching purple belt, he recognized the need for a more demanding training environment and transitioned to Gracie Barra – Belo Horizonte, a significant step up in both instruction and sparring quality.

His admiration for Felipe Pena — known throughout the BJJ world by the nickname "Preguiça" — eventually drew Lambertucci to Pena's FP Team, which operates in affiliation with Gracie Barra. He joined the group in January 2016, beginning nearly six years of intensive development under one of the sport's elite competitors and coaches. The journey was not without setbacks; multiple knee injuries interrupted his colored-belt career and tested his resolve. Despite those obstacles, Lambertucci continued to accumulate meaningful results across both the IBJJF and AJP circuits. Felipe Pena formally promoted him to black belt on December 17, 2020.

Among the most defining moments of Guilherme Lambertucci's development was a period of deep personal uncertainty that coincided with his early years at FP Team. Enrolled in law school but disconnected from the subject matter — having already abandoned other fields of study — he faced a genuine crossroads. The financial precariousness of a professional BJJ career made committing fully to the sport a daunting prospect.

As Lambertucci told BJJ Heroes, this crossroads coincided with his conversion to Christianity: "At the time I was starting law school. I was very unsure about my future because I didn't like my course and I had tried other subjects which I also didn't find appealing. Jiu-Jitsu was the only thing that warmed my heart, but there was no financial security in the sport (…). This time coincided with my conversion to Christianity. In my desperation, I decided to pray for enlightenment, for the right path. The following day, while in church, a guy I had never met before introduced himself to me, he was a fellow member of the parish who was looking for a grappling coach for a community project he was developing. He had learned I was a BJJ athlete and asked if I was interested. I took this as a sign of God, to follow my career as a sportsman."

That chance encounter resolved his indecision and committed him to jiu-jitsu not only as a competitor but as a coach and community figure — a dual identity that has defined his career ever since.

Competing in the super-heavyweight division at 100.50 kg (222.0 lbs), Guilherme Lambertucci established himself as one of the standout super-heavyweights of his generation across both the Abu Dhabi Jiu-Jitsu (AJP) Tour and the IBJJF circuit. His colored-belt record reflects a competitor who consistently threatened at the highest levels of amateur competition well before his black belt promotion.

Brown Belt Breakout

At brown belt, Lambertucci delivered two of his most significant pre-black belt performances: a gold medal at the 2018 CBJJ Brazilian Nationals No-Gi and a gold medal at the 2019 AJP Grand Slam London, the latter demonstrating his capacity to perform on an international stage against elite brown and black belt opposition. He also reached the final of both the 2019 IBJJF European Open and the 2019 AJP Abu Dhabi World Pro, finishing second in each — results that signaled he was on the cusp of black belt-level dominance.

Black Belt Validation

Following his promotion in December 2020, Lambertucci wasted no time validating his standing at the sport's highest level. In 2021, he claimed gold at the IBJJF South American Championship No-Gi in his weight division and won the AJP Brazilian National Pro, confirming his status as a legitimate super-heavyweight force on the black belt circuit. His willingness to compete beyond his weight class further underscored the breadth of his game: a silver medal in the absolute division at the 2021 IBJJF South American Championship No-Gi demonstrated that his skill set was capable of troubling athletes from heavier divisions as well.