Melissa Cueto was born on June 21, 1990, in Pelotas, a municipality in the Brazilian state of Rio Grande do Sul. After exploring a range of sporting activities in her youth, she found her way to martial arts in her early teens — entering combat sports not through jiu-jitsu, but through taekwondo, the Korean Olympic striking art. She trained taekwondo for three years, developing her competitive instincts and building the discipline that would later define her grappling career.

Cueto's path to BJJ was not without resistance. During the 1990s, jiu-jitsu in Brazil — particularly in Rio de Janeiro — carried a reputation for ties to violent street culture, and her parents were firmly opposed to her involvement in the sport. Taekwondo served as a workable compromise, allowing Melissa to pursue martial arts while respecting her family's concerns. Over time, she persuaded her parents to let her try jiu-jitsu, which she began at the age of 17. From that point forward, she committed entirely to BJJ, setting aside her striking background to embrace the grappling discipline she had long sought to pursue.

Cueto's formative years in jiu-jitsu were shaped by her first instructor, Antônio Pedro Dias — known in the community as Kapincho — who guided her from white belt through brown belt. Under his direction, she established herself as one of Brazil's most decorated colored belt competitors. At purple belt, she claimed back-to-back gold medals at the IBJJF South American Championship in 2016 and 2017, demonstrating the kind of consistent international-level performance that marked her as a rising force in the sport. Her ascent continued at brown belt, where she captured the World Championship gold medal in 2018 — a result that confirmed her readiness for the black belt ranks.

As her competitive profile grew, her relationship with her original coach deteriorated, and she sought new mentorship. She turned to Leonardo Morosetti of Thork Jiu-Jitsu, a coach she had known since her blue belt days. Morosetti welcomed her into his academy and guided her through the final stages of her development, ultimately promoting Melissa Cueto to black belt in December 2018 — a milestone that honored both her technical maturity and her record of achievement across multiple belt levels.

Building a Black Belt Foundation (2019)

Following her black belt promotion at the close of 2018, Cueto wasted little time asserting herself on the international circuit. In 2019, she joined forces with Diego Unfer, a representative of the RMNU Association, and quickly made her presence felt — finishing as runner-up at the IBJJF American Nationals and earning a bronze medal at the World Championship that same year. These early results signaled a smooth and confident transition into the black belt division.

Joining Alliance and Claiming World Gold (2021–2022)

In 2021, Cueto made a defining team affiliation change, joining Alliance — one of the most storied and successful organizations in the history of Brazilian Jiu-Jitsu. The partnership proved immediately productive. Later that year, she claimed gold at the IBJJF World Championship, announcing herself as a legitimate title contender at the sport's highest level. The following year brought further validation, as she added gold at the 2022 Pan Jiu-Jitsu IBJJF Championship to her growing collection of black belt titles.

A Complete Season and Sustained Dominance (2023–2025)

The 2023 season represented her most complete performance to date. Cueto won the heavyweight division title at the IBJJF World Championship while also earning a bronze medal in the absolute category — a double result that demonstrated both divisional dominance and competitiveness across all weight classes. She added gold at the IBJJF American Nationals that year, reinforcing her consistency across different competitive formats.

Cueto carried that momentum into 2024. At the IBJJF European Championship, she took gold in the heavyweight division alongside a bronze in the absolute — a composed, disciplined start to the calendar year. She replicated this result at the 2025 IBJJF European Championship, again winning the heavyweight title while earning a bronze in the absolute, underscoring the consistency she has brought to the European stage in consecutive years. Later in 2024, she added a bronze at the IBJJF World Championship, maintaining her standing among the elite of the heavyweight division against an increasingly competitive field.