Meet the collective
Critical Collective is powered by three leaders who believe strong outcomes start with strong relationships. The team blends expertise in strategy, programming, and implementation with a strong foundation in convening and engagement. Every engagement is shaped with intention, structure, and space for meaningful collaboration. Clients can expect thoughtful partnership, practical tools, and experiences designed to move work forward. Get to know the team bringing clarity, creativity, and connection to every engagement.
Thoughtful Partnership
Clear Communication
Intentional Collaboration
Our Team
Co-founder, President of Strategy & Development
Executive Strategy Architect | Social Impact Strategist | Culture & Systems Shaper | Partnership Builder | Servant Leader
Brittany Williams is a mission-driven executive leader with 10+ years of experience advancing equity-centered strategy and social impact across public, private, and nonprofit sectors. She is passionate about creating equitable spaces where people feel supported, respected, and able to thrive. Across her career, Brittany has helped organizations translate values into practice by building strategies, programs, and systems that strengthen community outcomes, expand access, and improve how institutions serve people, especially those most impacted by structural inequities.
Her work has consistently centered community voice, trust-building, and measurable impact. Brittany has led large-scale initiatives that align funding, partnerships, and operations to deliver results, including stewarding multimillion-dollar portfolios, shaping evidence-informed program approaches, and strengthening cross-sector ecosystems. Known for turning complex challenges into clear plans, she brings a blend of strategic planning, program development, and operational leadership that helps teams move from ambition to execution, with accountability and care built in.
Brittany holds a Master of Nonprofit Management from DePaul University and a Bachelor of Arts in Communications from the University of Missouri. She also brings deep community-rooted leadership through nonprofit board and volunteer service, and she approaches every team environment with a collaborative, people-first leadership style. Brittany is especially committed to strengthening the teamwork, alignment, and culture of the spaces she enters, believing that sustainable change requires both strong relationships and strong systems working together.
Co-founder, President of Culture & Education
Corporate Strategist | Social Impact Agent | Educator | DEI Practitioner
Donald D. Gilliam is an accomplished corporate strategist, educator, speaker, author, Diversity, Equity, and Inclusion (DEI) practitioner, and Certified Systems Thinking Associate (CSTA) with 13+ years of experience in organizational development and employee engagement. Donald exists at the intersection of curiosity, innovation, candor, and humor. Donald partners with executive leaders and teams through a consultative approach grounded in critical discovery, collaborative problem-solving, and sustainable impact. His work focuses on driving transformative practices that strengthen daily operations, organizational culture, and business outcomes. Through intentional, strategy-driven conversations, Donald helps organizations execute effectively, boost employee engagement, and build inclusive systems that align mission, talent, and goals.
Known for translating complex organizational challenges into clear, actionable strategies, he has led initiatives in training, talent development, and sustainable culture change across multiple industries. Previously, as the inaugural Director of Diversity, Equity, & Inclusion at National Louis University, he co-authored a DEI framework embedded into the university’s 5-year strategic plan. His work focused on optimizing talent acquisition, addressing retention and engagement gaps, and strengthening performance management and succession planning processes. Donald credits his time as Program Instructor of the award-winning Mizzou Black Men’s Initiative at University of Missouri (Mizzou) as the catalyst for his career in organizational development and inclusion. There he championed critical self-examination and collective reimagining as tools for transformative change.
A proud native of Chicago's South Side, Donald holds a M.Ed. in Educational Leadership and Policy Analysis and a B.G.S in Business Marketing and Communication from the University of Missouri (Mizzou). His perspective-driven approach to strategic alignment and empathic leadership reflects his commitment to delivering high-quality, solution-oriented work that creates scalable, long-term impact.
Co-founder, President of Strategic Events & Experience Design
Architect of Experience | Strategic Event Visionary | People Connector | Champion of Thoughtful Engagement
Mariah D. Cater is an event and experience leader with over a decade of experience creating thoughtful, high-impact programs across corporate, nonprofit, healthcare, and hospitality spaces. Known for her ability to blend strategy with creativity, she brings a collaborative, detail-driven approach to every experience she leads—ensuring events feel intentional, seamless, and meaningful.
Currently, Mariah serves as the Co-founder and President of Strategic Events & Experience Design at Critical Collective, where she leads the vision, strategy, and execution of purpose-driven experiences for organizations seeking meaningful engagement and measurable impact. Alongside this work, she lends her expertise as Experience Manager for McDonald’s Worldwide 2026 Conference and Event Consultant for ADM, applying her expertise across large-scale, high-visibility programs that further inform, strengthen her leadership in experiential strategy and the work she brings to her clients.
Previously, Mariah led strategic and industry events at Press Ganey and managed community-focused initiatives for organizations such as Chick-fil-A, Code.org, Medscape LIVE, and the Nike Tournament of Champions. With a background in Marketing and Public Relations from Columbia College Chicago, she is known for her thoughtful leadership style, strong operational instincts, and passion for creating experiences that leave a lasting impression.
