Electoral system design has played a pivotal role in shaping Sri Lanka’s post-independence political trajectory, influencing the nature of representation, the structure of the party system and the quality of governance. This article critically examines the evolution and impact of electoral reforms associated with 19A. It traces the historical development of Sri Lanka’s electoral system, analyses the core features of the post-19A reform package—including the move towards a mixed-member proportional model, the capping of preferential votes, changes to local government electoral rules and the strengthening of the independent Election Commission—and evaluates their effects on political representation and governance. Particular attention is paid to parliamentary representation and party system change, the representation of ethnic and religious minorities, and the evolving position of women and youth in formal politics. Using evidence from the 2015 and 2020 parliamentary elections and the 2018 local government elections, the article assesses how institutional changes have altered patterns of competition, coalition formation and accountability. The analysis finds that the reforms have modestly improved the integrity and inclusiveness of elections, enhanced the visibility of local representatives and women councilors, and created stronger institutional checks through independent commissions. However, significant challenges remain, including political resistance and institutional inertia, legal and administrative complications, weak campaign finance regulation, and limited public understanding of complex mixed-member rules. Drawing on comparative experiences from other mixed-member and hybrid systems, the article concludes with policy recommendations aimed at consolidating and deepening the democratic gains initiated by the Nineteenth Amendment.