The Brain Trust


Denielle Sachs – Managing Director

Denielle is an impact strategist, organizational leader, and coalition-builder with extensive experience in the board room and in the field. She has a unique ability to turn ideas into action, skillfully manage complexity, and craft powerful alliances between unlikely collaborators. She advises a range of organizations, including philanthropists looking to launch new organizations, companies building or restructuring corporate responsibility initiatives, and enterprises looking to attract impact investment. Over the last two decades, she has built organizations, boards and coalitions from the ground up, designed culture and thought leadership strategies that ignite movements, and led special projects for Fortune 500 businesses. She founded The Tembo Group after seven years as the Director of Social Impact for McKinsey & Company, where she architected and led the firm’s first ever, global corporate citizenship strategy. She also helped build McKinsey’s corporate foundation and its first program. She’s served as a press lead at The White House, sits on several boards and advisory councils, including for The Resolution Project, Opportunity Collaboration and Breakout Foundation. She is a ForbesWomen contributor, a prolific speaker and writer on multiple topics, and holds an M.A. in International Development from the School of Oriental and African Studies and a BA from New York University.

Brian Ackerman – engagement manager

Brian Ackerman is Engagement Manager at The Tembo Group, where he manages daily client interaction, workflow, timelines, and deliverables. Prior to joining The Tembo Group, Brian spent over a decade in advocacy, management consulting, and media. In 2016, Brian co-founded Archetypal Media, a boutique agency specializing in institutional partnership development, digital marketing, and creative services for nonprofits focused on reducing health disparities. Before that venture, Brian spent a decade in Washington, DC advocating to improve young people's access to sexual and reproductive health resources at Advocates for Youth, consulting on higher education marketing and enrollment strategy at Education Advisory Board, and developing innovative advertising solutions for universities and nonprofit organizations at Foreign Policy magazine. Along the way, he did his graduate research in political geography at the Federal University of Rio de Janeiro studying civic participation spaces in Brazil and the United States on a Rotary Ambassadorial Scholarship. Brian completed his undergraduate degree in International Affairs at The George Washington University and now lives in Brooklyn, NY.



Diana Walker — Partnerships Advisor

Diana has more than 15 years of experience building high impact, cross-sector alliances and thought leadership positioning within frameworks such as the Millennium and Sustainable Development Goals, ESG investment frameworks, Bcorps, and social entrepreneur investment funds. As Founder and CEO of Walker Impact Strategies, Diana works with businesses, governments, entrepreneurs, and philanthropists to develop innovative and measurable for-impact investment and partnership strategies. Most recently, Diana has led strategy and partnerships for corporations, including Caterpillar, Guggenheim Investments, Chobani, Dell, Blackbaud, AnswerLab, Techstars, and others. She has worked with social impact groups, including the Skoll Foundation, TED, Climate Reality Project, members of the UK Royal Family, and is leading programming curation for The Conduit in London, support in building the Global Goals Hub in Davos during the World Economic Forum, and building and leading coordination for Global Goals Week in New York during UN Week. Diana previously worked for 12 years at the United Nations Foundation and in national politics, including working on presidential campaigns, a presidential inauguration and collaboration with the White House Administration. Diana is Chair of the Social Sector Accelerator, and sits on the Board of Counterpart International in Washington, DC and the Posner Center in Denver, CO. She is a member of the BMW Foundation’s Responsible Leaders Forum and has spent time mentoring young social entrepreneurs through the Resolution Project’s Guide Program. Diana was named by the Diplomatic Courier and Young Professionals in Foreign Policy as one of the top 99 young foreign policy leaders. Diana currently resides in Denver, CO and on an airplane and loves to spend her time traveling the world and in the outdoors.

National Advisors


Christina Lindstrom

Impact Measurement & Assessment Advisor


Andi Cross

Marketing Advisor