Zachary Kaina

Zach Kaina was born on May 23, 2002, in Oahu, Hawaii — a state with a deep and celebrated connection to martial arts. His first exposure to combat sports came at age 5 through karate, though the striking-based discipline failed to hold his interest. The path toward jiu-jitsu opened through his family's awareness of BJ Penn, the iconic Hawaiian fighter who became a two-division UFC champion and, more significantly for the grappling world, the first American to win an IBJJF World title in the adult black belt division. Penn's legacy loomed large in Hawaii's martial arts culture, and when Kaina's interest in karate faded, his mother wasted little time enrolling him in a local jiu-jitsu school.

Beginning his grappling education at age 6 under Mike and Chris Onzuka of Team O2 — later supplemented by instruction from Kyle Nitahara — Kaina proved to be a natural on the mat. Over the course of his childhood years in Hawaii, he earned every belt from white through orange, building the technical foundation and competitive instincts that would define his career trajectory. By the time his family made the decision to relocate, Kaina was already deeply embedded in jiu-jitsu culture and primed for the next stage of his development.

At age 10, Zach Kaina moved with his family to Costa Mesa, California, arriving at Art of Jiu-Jitsu Academy as an orange belt and enrolling in the Believe & Achieve kids program — one of the most accomplished youth development curriculums in competitive Brazilian Jiu-Jitsu. Under the coaching of Guilherme Mendes, Kaina quickly distinguished himself as one of the program's top performers, demonstrating both the technical aptitude and competitive drive that AOJ's elite environment demands.

What followed was one of the more complete development stories in modern BJJ. Kaina progressed through every remaining belt rank — from orange to brown to black — entirely within the AOJ system. The continuity of instruction, competitive exposure, and technical culture at AOJ shaped every dimension of his game. On December 9, 2023, Guilherme Mendes formally promoted Kaina to black belt, marking the culmination of more than a decade of uninterrupted development within a single elite program. Few competitors in the current generation can point to such an unbroken lineage from early childhood through professional-level achievement.

Long before his black belt promotion, Zach Kaina had already established himself as one of the most decorated young competitors in IBJJF competition. His juvenile years produced an exceptional run of international results, highlighted by capturing both the IBJJF World Championship title and the IBJJF World No-Gi Championship title in 2018 — a remarkable double for any competitor at that stage. That same year, he also claimed gold at the 2018 IBJJF Pan Jiu-Jitsu Championship and the 2018 IBJJF European Open Championship, underscoring just how dominant his performances were across multiple events and formats.

His progression through the colored belt divisions maintained that competitive standard. At purple belt, Kaina took first place at the IBJJF American Nationals in 2020, while adding podium finishes at the IBJJF Pan Championship and American Nationals across 2020 and 2021. The brown belt years, however, signaled something closer to a pre-black belt statement. In 2022, Kaina won the IBJJF World No-Gi Championship at brown belt — a result that carried unmistakable weight as an indicator of elite potential — while also earning podium finishes at the IBJJF World Championship, IBJJF Pan Championship, and IBJJF American Nationals in both gi and no-gi formats. Taken together, his colored belt career painted the picture of a competitor developing with rare consistency toward the sport's highest level.

Zach Kaina competes in the 61kg light-featherweight division, and his ascent at that weight class in the black belt ranks has been both swift and methodical. In his first full year competing as a black belt, he reached the final of the IBJJF World No-Gi Championship in 2023, finishing as runner-up at 61kg — a performance that, for a newly promoted black belt, represented a significant arrival on the world stage.

The following year delivered the decisive answer. At the 2024 IBJJF World No-Gi Championship, Kaina returned to the 61kg division and claimed the title outright, completing the progression from runner-up to champion in the span of a single competitive cycle. The victory stands as the defining achievement of his black belt career to date and confirms his place among the elite competitors globally in his weight class.

The arc from 2022 through 2024 — brown belt World No-Gi champion, black belt World No-Gi finalist, black belt World No-Gi champion — reflects a level of sustained upward momentum that is rare even within the high-performance environment of Art of Jiu-Jitsu Academy. Shaped from early childhood by the AOJ system and Guilherme Mendes, Kaina has translated years of structured development into results at the sport's most prestigious stage.