This paper analyses the mutual influence and self-perpetuating cycle of legitimacy of EU legal scholars and the Court of Justice of the European Union (CJEU) in expanding and broadening the free movement rights of Union citizens and their family members. It is argued that legal scholars have played a dual role in promoting the constitutional paradigm of an ever-expanding scope of directly enforceable residence and movement rights in the EU. First, by presenting the expansion of free movement rights as an inevitable outcome of the EU constitutional order based on directly enforceable individual rights, scholars have played a significant role in legitimizing the jurisprudence of the Court in the face of initial resistance from the member states. Second, legal scholars have been an important source for the Court of Justice in developing its case law in this area. The Advocates General in their opinions have drawn on an expanding field of scholarship presenting the expansion of free movement rights as an inherent feature of the EU as a constitutional legal order. Spurred by the objective of turning the EU into more than an internal market, the opinions of the Advocates General have mostly been followed by the Court. Legal scholars have thus served not only as a legitimizing force, but also as a source of inspiration for the perceived constitutionalization of free movement rights in the EU.