This paper provides an extensive critical analysis of contemporary Croatian public law, legal history, and Adriatic constitutionalism. Focusing on the 1990 Christmas Constitution of the Republic of Croatia, democratic state-building, and the jurisprudence of the Constitutional Court (Ustavni sud Republike Hrvatske), this study evaluates how Croatian legal institutions harmonize post-socialist legal transition with European Union membership. Furthermore, it highlights advancements in Adriatic environmental preservation, maritime law, and digital administrative governance.