Tides Expands Leadership Team with New Officers, Michael Mosby, Gwen Tillman, and Dan Shannon

Molly DeCoudreaux Photography, Tides, Tides Foundation, head shot

As we emerge from an unprecedented and transformative year, Tides’ work and that of our partners remains crucial. Bold and innovative leadership is essential, not only to recognize the gravity of today’s challenges, but to understand the unique role Tides plays in addressing them. This is the type of leadership we’re proud to say we already have among our Board, executive team, staff and partners— and now we are adding even more talent to the team.

We are proud to announce that interim chief operating officer, Michael Mosby, has been officially named COO. In addition, Gwen Tillman joined Tides as our new chief people officer on January 11, and Dan Shannon will begin as chief partnerships officer on February 22. Each will play key roles as Tides enters its 45th year of pioneering innovative solutions to address society’s most critical issues.

Michael Mosby, Chief Operating Officer

Michael joined Tides in 2017, having served several roles since, including business process manager; director, Business Process Redesign; and most recently, interim chief operating officer. Prior to joining Tides, he spent more than 15 years at Lawrence Livermore National Laboratory, where he operated as a certified skilled leader, project manager, and facilitator in process and performance management, measurement, and improvement. In addition to the Laboratory, he has been recognized for building efficient and effective solutions for the Department of Energy and United States Army. Michael brought his knowledge and experience to Tides four years ago to help build solutions focused on accelerating the pace of social change.


Gwen Tillman, Chief People Officer

Gwen brings to the organization more than 15 years of experience working with nonprofits, and more than two decades of leadership honed while building and driving global people programs for premiere high-tech companies. In her most recent role as vice president of People Development & Community Engagement at AppDynamics, Gwen worked with leaders and employees at all levels across the business to grow and express their leadership in ways that are personally meaningful, while also generating the intended organizational outcomes. As chief people officer for Tides, she is responsible for leading all aspects of Tides’ human resources, including designing and implementing people strategies and solutions for the organization and its key partners to strengthen capacity and deliver on their missions.


Dan Shannon, Chief Partnerships Officer

In his most recent position as partner and managing director for Purpose, a leading social impact agency and consultancy, Dan collaborated with mission-driven organizations to design and implement strategies and campaigns aimed at mobilizing people to take action and create meaningful change. With a background in nonprofit campaigns, communications, and organizing, Dan has led projects with U.S.-based civil rights organizations, including the ACLU and Anti-Defamation League, as well as INGOs focused on global poverty and human rights, including UNICEF and the Bill & Melinda Gates Foundation. As chief partnerships officer, he will be responsible for leading Client Services; Strategic Partnerships; Tides Collective, and Marketing & Communications, as well as growing and deepening engagement with partners, including leading Tides’ business development strategies.


We are confident that we have put in place a leadership team that will continue to innovate and reimagine bold solutions as the world and its challenges continue to evolve.

The Tides global community is privileged and honored to welcome Gwen, Dan, and Michael into their new roles.

News & Press