About Us
At The Colby Group, we help leaders, philanthropists, and organizations turn purpose into measurable impact. We bring decades of experience leading at the intersection of business, social innovation, and systems change by helping clients move from vision to execution with clarity, curiosity, and results that last.
We have built and led organizations, advised global companies and foundations, and coached executives navigating what’s next. Our work is grounded in a belief that when purpose, strategy, and leadership align, impact follows—and ripples outward.
We believe that purpose, curiosity, and commitment drive the results that matter most. Purpose keeps leaders anchored to what truly matters. Curiosity opens space for new ideas, better questions, and bold solutions. Commitment turns insight into motion and motion into lasting change.
We start by listening deeply to your goals, your culture, and the realities that shape your work. Then we work together to focus on where purpose intersects with performance. We help you find clarity where there is noise, connection where there is friction, and momentum where progress has stalled.
Our work is not about delivering reports (although we do build some great ones!). Instead, our real value is in helping to build capability, confidence, and systems that last. We engage as partners, not vendors, and work shoulder-to-shoulder with clients to design solutions that stick, accelerate progress, and scale results.
We are driven by the ripples of impact that occur when the leaders and teams we serve inspire others to act with greater purpose, curiosity, and courage. Those ripples extend beyond organizations to shape how people lead, collaborate, and make a difference in the world.
Meet the team
Liz McCartney
Principal
Liz McCartney is a social entrepreneur and nonprofit executive recognized for her work in disaster recovery, resilience, and organizational transformation. As co-founder and COO of SBP, she led the growth of a small recovery initiative into a national organization that rebuilt more than 7,000 homes, launched innovations in affordable housing, and raised over $400 million for communities impacted by disaster.
A Toyota Production System practitioner, Liz is passionate about efficiency, problem-solving, and continuous improvement. She’s known for helping leaders and teams design strategies, strengthen systems, and scale impact. Her expertise spans strategic planning, team-building, fundraising, affordable housing development, board governance, and philanthropic advising.
Liz has been recognized as a CNN Hero of the Year, a White House Champion of Change, and she received the HUD Secretary’s Award for Public-Philanthropic Partnerships. She holds a B.A. from Boston College and an M.A. from George Washington University, was awarded an Honorary Doctorate from Muhlenberg College, and completed executive training at Harvard Business School. She is currently on the Board of the Martha’s Vineyard YMCA.
Liz lives in Massachusetts and Puerto Rico. When not working, she enjoys a growing meditation practice, listening to podcasts, playing tennis and cooking with her son.
Zack Rosenburg, ESQ.
Principal
Zack is a visionary CEO, innovator and coach with a demonstrated ability to solve complex problems, turn ideas into thriving businesses and achieve transformational goals. His career evolved from his work as a trial lawyer to becoming a successful founder and CEO who drove impact through problem solving, values-based leadership and a dogged commitment to impact. Along the way – and after visiting New Orleans on a volunteer trip six months after hurricane Katrina – he co-founded and scaled a national NGO that is transforming disaster resilience and recovery in America and the Caribbean. His successful professional experience is the result of his ability to make deep connections and build trust. His practice is rooted in the unwavering belief in human capacity.
Zack advises and coaches policymakers, executives and Boards. Zack has been featured in major media outlets including CNN, CBS News, and the Wall Street Journal. A sought after speaker, he has been a key-note speaker at NASDEQ, Clinton Global Initiative, US Chamber, and the Aspen Institute on topics ranging from disruptive innovation to corporate culture to outcome-driven philanthropy.
Zack is an ICF-trained Executive Coach and a World Economic Forum Schwab Fellow. He has served on various local and national boards and advises several startups. Zack lives with his wife and son between Puerto Rico and Massachusetts. An avid golfer, he has an uncanny ability to help the people playing alongside him find their best game.
Zack Rosenburt, ESQ., Principal
Services
Coaching
Consulting
Philanthropic Advising
Fractional Engagements
