Agricultural transformation is vital to sustainable development, allowing food security to be reconciled with environmental sustainability. However, the complex interplay between agricultural modernization and environmental systems, particularly the role of economic drivers, remains insufficiently understood. This study addresses this gap by analyzing the Fujian Province, a representative hilly region in southern China, during the period 2005–2021. We construct a comprehensive agricultural transformation evaluation index based on the “elements, structure, and function” framework and apply a modified coupling coordination model. Using random-effects and moderation-effect models, we assess the impact of agricultural productive services on this coordination and investigate the moderating role of agricultural industrial agglomeration. Our analysis identifies four distinct types of agricultural transformation in Fujian and shows that the overall coupling coordination degree improved steadily, rising from low to basic coordination over the study period. Agricultural productive services significantly enhance coordination, although their effects vary across transformation types. In addition, agricultural industrial agglomeration amplifies the positive influence of productive services, indicating a synergistic mechanism that supports sustainable agricultural development. These findings provide policy-relevant insights for East Asian economies with similar land endowments as well as for hilly regions worldwide.