Robert Diggle was born on February 13, 1992, on Long Island, New York, and holds dual Italian-American citizenship through his grandfather. His introduction to jiu-jitsu came at age 18, when securing a part-time job gave him the financial means to afford training — a practical turning point that set the course for his athletic career. From the outset, Diggle pursued competition alongside a serious academic life, eventually earning a philosophy degree from Queens College, City University of New York.

As his competitive profile grew, Diggle adopted the alias "Degle" on social media as a deliberate way to keep his academic and athletic identities separate — a strategy that reflected a thoughtful awareness of how each world might perceive the other. That online presence gained enough traction to open professional opportunities in jiu-jitsu, and he ultimately chose to invest more deeply in competition rather than pursue the Ph.D. programs he had been considering.

Diggle's development as a grappler unfolded across several gyms in the New York area, each shaping a distinct phase of his technical growth. He began training under Chris Schlesinger before transitioning to Kioto, where he worked under Milton Regis. He subsequently joined Vitor Shaolin's Manhattan gym, where training alongside Gregg Depasquale proved formative — Depasquale promoted Diggle to purple belt.

The next major chapter came through his association with John Danaher, one of the central architects of the modern no-gi movement, who awarded Diggle his brown belt. Diggle received his black belt from Brandon Bennett of the Renzo Gracie Academy on August 9, 2021 — formalizing a journey built almost entirely within the no-gi grappling circuit. Between 2018 and 2020, he accumulated twelve Grappling Industries titles at the colored belt level, a testament to his consistency and finishing ability long before reaching the sport's highest rank.

Throughout his career, Diggle has operated as a submission-first competitor with little interest in accumulating points. His approach centers on finishing matches, and leg locks — heel hooks in particular — serve as his primary weapon. That identity was on full display at the 2021 IBJJF American National No-Gi Championship, where he competed at brown belt and won every match by heel hook, claiming gold in one of the most dominant performances of his pre-black belt career.

Diggle competes almost exclusively in no-gi formats, and his name appears regularly on high-profile submission grappling platforms including Polaris, Grapplefest, and Fight To Win. His sustained output across those circuits has produced over 60 wins at black belt, reflecting both his exceptional finishing rate and the breadth of competition he has consistently sought out.

2022 ADCC West Coast Trials

Diggle's performances on the ADCC circuit demonstrated that his submission-hunting style translates effectively to the sport's most demanding no-gi environments. At the 2022 ADCC West Coast Trials in the -66kg division, he reached the semi-finals, with a submission of CJ Murdock among his standout victories along the way. While he fell short of full qualification, the run confirmed his standing as a legitimate contender within the elite no-gi landscape.

ADCC Open Double-Division Performance

Also in 2022, Diggle produced a particularly impressive showing at the ADCC open level. He won the 66kg division at the ADCC Sweden Open, submitting every opponent he faced, then repeated the feat at the ADCC Singapore Open — this time in the 77kg division, again finishing the entire field by submission. Competing across two weight classes and submitting every opponent in both represents one of the most complete stretches of his competitive career.

On September 20, 2020, Diggle submitted UFC bantamweight Sean O'Malley at a Grappling Industries event in Phoenix, finishing the match with a heel hook — entirely consistent with the submission-hunting identity that defines his competitive approach. At the time, O'Malley was a rising figure in the UFC's bantamweight division, which gave the result an immediate visibility that extended well beyond the grappling community.

The outcome drew significant online commentary, with much of the response framed around the argument that a grappling result carries no relevance to MMA performance. Diggle engaged directly with that criticism, drawing a clear distinction between submission grappling and mixed martial arts. He acknowledged openly that O'Malley would hold a meaningful advantage in a striking-based MMA context, while maintaining that the two rule sets are separate disciplines that deserve evaluation on their own terms. The match became a minor flashpoint in the recurring public debate over how grappling-only results should be interpreted relative to MMA records.

In 2020, Diggle relocated to Singapore to lead the no-gi program at Evolve MMA, one of Asia's most prominent martial arts organizations. The position placed him at the head of a high-level program within an institution long known for attracting world-class talent across multiple disciplines, marking a significant international chapter in both his coaching and competitive career.

Diggle returned to North America in late 2021 and joined B-Team Jiu-Jitsu in Austin, Texas. His move to B-Team came in the wake of the widely documented split of the Danaher Death Squad, the influential New York-based training collective with which Diggle had long been associated through his work with John Danaher. B-Team rapidly assembled a roster of former DDS members and established itself as one of the top competitive grappling teams in North America. Diggle's trajectory — from the New York no-gi circuit to Singapore to Austin — reflects the increasingly global structure of elite submission grappling and the fluid team affiliations that define the sport's upper tier.