Implementation arrangements are increasingly recognized as a decisive factor in the success of contemporary welfare policies, particularly those that combine income support with activation requirements. This paper examines the Italian case of minimum income schemes - the Reddito di Inclusione and the Reddito di Cittadinanza - to explore how local implementation arrangements shape one of their core objectives: reintegrating beneficiaries into the labour market. Drawing on an original dataset that integrates administrative data with a unique INAPP survey of local institutions, we operationalize “implementation arrangements” along three dimensions: institutional capacity, alignment between organizational missions and policy goals, and the quality of institutional cooperation within a multilevel governance framework. Using regression models at the municipal level, we find that implementation strength matters, but horizontal cooperation and effective communication between Public Employment Services (PES) and Local Social Planning Institutions (LSPIs) emerge as the strongest predictors of successful outcomes. While PES performance is central due to their policy mandate, LSPIs’ ability to foster integrated networks also contributes positively when well-coordinated. These findings highlight that policy success depends less on formal design than on the quality of local governance and institutional complementarities. The results provide new evidence for the literature on implementation, underscoring the importance of horizontal multilevel governance in active social policies.