In 2022, environmental, social, and market pressures are increasing the urgency for sustainable solutions and the demand for sustainability leadership. Despite this increasing demand, product and packaging designers at traditional creative design agencies continue to perpetuate unsustainable design behavior causing negative impacts on people, the planet, and future profit. Through a qualitative research study, academic research, and firsthand narrative evidence, key barriers to sustainable design implementation are discovered at the systems level of traditional creative design agencies. This thesis introduces a systemic solution to effectively change the leverage point - and therefore impact– of sustainable design at traditional creative design agencies. There are four key insights from this thesis: 1) Defining the optimal leverage point for sustainable design in an agency setting; 2) Proposing both bottom-up and top-down sustainable design leadership approaches to empower designers, increase capabilities, and support organizational transformation; 3) Advocating for organizational transformation using a complex adaptive system (CAS) model to create the capacity to adapt to environmental, social, and market pressures; 4) Advancing the field of sustainable design by identifying and defining a new-to-industry sustainable design leadership role, the Design Director of Sustainability, to engage sustainability at the optimal leverage point and provide domain expertise to create accountability for sustainable solutions. This thesis output provides actionable tools for both purpose-driven designers and creative design agencies to increase capabilities, build resiliency, and create adaptability to support the emerging future.