Gareth Holebrook works with executives, senior engineers, and coaches on the governance of sustained performance.

A former Royal Navy engineer and agile transformation specialist, he has led teams at Visa and partnered with L. David Marquet on Intent-Based Leadership. His work addresses the gap between committing to difficult outcomes and maintaining coherence under pressure without drifting into burnout.

He has completed in dozens of ultra-endurance events, the the Ironman World Championship in Hawaii and the Kiwiman Double Extreme Triathlon. The discipline required to persist without breaking translates directly to leadership, engineering and organisational change.

The Ishi Spiral emerged from this intersection. His book, Ishi: The Discipline of Determined Intent, launched in January 2026 and establishes the discipline of self-governance grounded in Japanese philosophy, deep theory and lived practice.

He writes regularly on Substack at https://substack.com/@garethholebrook and speaks on disciplined persistence in North America and Europe.