The European Green Deal (EGD) represents a transformative policy initiative, heralded as Europe’s “man on the moon” moment, aiming to achieve climate neutrality by 2050 while fostering social equity and economic resilience across the European Union (EU). From its inception, the EGD was intended to integrate environmental sustainability into governance frameworks and define an all-encompassing agenda to jointly address the urgent challenges of climate change, biodiversity loss, and social inequalities. This chapter explores how the EGD, when positioned as a nascent eco-social contract, could redefine the roles and responsibilities of each European societal actor by aligning ecological responsibility with economic and social objectives, guided by the principle of common but differentiated responsibilities outlined in the Paris Climate Agreement. It examines the role of the EU’s multilevel governance structure in embedding the EGD’s policies, the systemic barriers to its implementation, and the pathways for overcoming these challenges. By critically analysing what the EGD’s opportunities and limitations have been, the chapter offers insights into how the EU can lead global sustainability efforts and foster a more inclusive and sustainable future.