The Brimstone Story

Brimstone was never a traditional consultancy. It was born from real leadership experience, rooted in bold thinking, and grounded in action. Founded by Bob Weiler and Bob Marcus, Brimstone brought a unique energy to the consulting world—one that emphasized results, resilience, and relationships.

For over 40 years, Brimstone partnered with extraordinary leaders to catalyze business transformation. From Fortune 500 companies to fast-growing enterprises, Brimstone helped senior teams align, accelerate, and execute—working side-by-side with CEOs and their teams to move from strategy to results.

At the heart of Brimstone’s methodology is a belief in purposeful action. Their proprietary approach blended organizational alignment, executive development, and large-scale change activation into a unified path forward. Whether helping a company lead through post-merger integration, build leadership team cohesion, or accelerate business performance, Brimstone always focused on what mattered most: changing the way work gets done to deliver breakthrough results.

Bob Weiler’s background shaped the firm’s DNA. Before founding Brimstone, he was CEO of Grand Circle Travel, helped pioneer the Outward Bound Professional Development Program, collaborated with leadership luminary Noel Tichy at GE’s famed Crotonville campus, and guided high-performing teams across disciplines—from corporate boardrooms to alpine expeditions. His commitment to pushing limits—physically, intellectually, and organizationally—became the foundation of the Brimstone ethos.

Known for its hands-on, embedded model and deep trust with clients, Brimstone became a sought-after partner for companies undergoing rapid change. Their work wasn’t about slide decks—it was about transformation you could feel, measure, and sustain.

In 2021, Brimstone joined forces with ZRG Consulting, becoming the cornerstone of ZRG’s Business Acceleration Practice. The move brought Brimstone’s powerful methodology to a global stage, integrated with ZRG’s broader capabilities in culture, leadership, and executive coaching.

Today, Brimstone’s legacy lives on inside ZRG—not just in frameworks or tools, but in the relentless commitment to helping leaders act with purpose, align with clarity, and accelerate with impact – but also as part of the Leadership Acceleration Practice.

‍