Abstract With a longitudinal and exploratory case study, the potential path of ambidextrous governance balance between contracts and inter-firm relationships is investigated through process models, to open the “black box” between IT and the balance of contracting-relationship and ambidextrous governance. It is found that achieving a governance balance between contracts and inter-firm relationships is the key to promote a sustainable inter-firm collaboration, while IT enables dynamic imbrication of governance mechanisms during such inter-firm governance, and thus achieving a balance of governance mechanisms with IT enabled governance continuous optimization. This study further extends the understanding of inter-firm governance theory, which inspires Chinese firms to promote sustainable collaborations under the internet environment.