Pedro Marinho was born on October 9, 1996, in Buzios, Brazil. From an early age, he embraced an active lifestyle, participating in various sports and martial arts disciplines. His martial arts journey began at age 7 with capoeira, a traditional Brazilian martial art known for its fluid movements and acrobatic techniques. During his teenage years, Marinho expanded his combat sports foundation by training in Thai boxing and Western boxing, sharpening his striking skills and physical conditioning. Shortly after turning 17, he discovered Brazilian Jiu-Jitsu, marking a pivotal turning point in his martial arts career.

Initially, Marinho trained under Master Reinaldo Fernandes at Brazilian Top Team (BTT), where he developed his foundational Brazilian Jiu-Jitsu skills. In 2017, he stood out among more than 1,000 applicants, earning a coveted spot in Felipe Pena's FP Golden Team scholarship program. This prestigious initiative aimed to cultivate Brazil's most promising grappling talents. Marinho relocated to Belo Horizonte to train directly under Felipe Pena, connecting him to the extensive Gracie Barra network and significantly accelerating his technical growth.

In November 2018, Marinho received an invitation from renowned instructor Ulpiano Malachias to join Gracie Barra Houston in Texas, USA. Recognizing the opportunity for greater exposure and advancement, he accepted and relocated to the United States. Under the mentorship of both Felipe Pena and Ulpiano Malachias, Marinho earned his brown belt. On March 13, 2021, he achieved a significant career milestone, receiving his black belt from Ulpiano Malachias. That same year, Marinho captured the IBJJF No-Gi World Championship title as a rookie black belt, solidifying his status among the elite competitors in the sport.

Pedro Marinho has firmly established himself as a leading no-gi specialist within the professional grappling circuit. Known for his aggressive wrestling style, Marinho consistently pressures opponents, dictating the pace and controlling exchanges. His signature guillotine choke has become a hallmark of his competitive arsenal, securing numerous submission victories against high-level opponents. Marinho's tactical approach combines relentless forward pressure with precise submission setups, making him a formidable competitor in any no-gi format.

In 2022, Marinho became the inaugural Who’s Number One (WNO) 205 lb champion by defeating renowned grappler Craig Jones. Demonstrating consistent dominance, he successfully defended his title multiple times against elite competitors, including Giancarlo Bodoni, Rafael Lovato Jr., and Izaak Michell. These victories further cemented his reputation as one of the top no-gi grapplers in the world, showcasing his adaptability, strategic mindset, and technical precision under pressure.

Representing Gracie Barra, Marinho competed at the prestigious 2022 ADCC World Championship in the 88 kg division. During this elite tournament, he tested his skills against some of the world's best grapplers, including a notable match against Lucas "Hulk" Barbosa. Additionally, Marinho showcased his versatility and competitive spirit by participating in the open-weight bracket, highlighting his willingness to challenge himself against larger opponents on grappling's biggest stage.