The global economy's transition toward more sustainable development models is undoubtedly grounded on small and medium-sized enterprises (SMEs). However, SMEs, individual entrepreneurs, and microenterprises have always encountered barriers to implementing social responsibility and sustainability concepts. The paper investigates the enabling role of formalized corporate networks to drive SMEs toward sustainable behaviors. A quantitative nonlinear regression approach is applied to a content analysis of a sample of network contracts coded. The content analysis is applied to analyze the declared objectives, the purpose of the contract, and sustainability areas. An ordered logistic regression is applied on variables related to the behavior of SMEs before entering in the contract and post-adhesion phases. Data demonstrates how networks of SMEs can be used as enabling factors to boost sustainability among them. Specifically, the study is based on a sample of 96 formalized network contracts (FNCs), including 1486 Italian SMEs in that sustainability-oriented networks. It offers an evidence-based perspective on how networks of companies can play a fundamental role in the development of policies aimed at bringing small companies closer to the concept of sustainability (such as eco-innovations, eco-efficiency, environmental performance, and social innovations, among others) and its practical implementation. This paper has two significant strengths. The first is that it uses as a sample a set of 1486 companies, including individual entrepreneurs and microenterprises, whose data are usually difficult to collect. The second is that it demonstrates the efficacy of a contractual form that could be scalable to different countries.