Abstract In the last three decades, scholars and operators have paid increasing attention to the environmental sustainability and energy efficiency of seaports. To achieve high competitiveness in seaports in response to environmental and energy regulation, port authorities (PAs), policymakers, port users and local communities have to invest considerable resources. This paper investigates the role of the managerial instruments in the decision-making processes of PAs for reducing and preventing negative environmental and energy effects from ports. This research consists of a two-step study. First, we conduct a literature review to analyse the academic views by systematically reading the reports to investigate practitioners’ views on the performance indicators for environmental sustainability and energy efficiency in the port industry. Second, we provide, through a qualitative method, a portrait of the Italian seaports and a multiple case study to confirm the developed conceptual managerial key performance indicators (KPIs). Specifically, applying the Balanced Scorecard model, this paper provides managerial KPIs to support PAs in their decision-making processes within the inter-organizational relationships with shipping lines for developing environmentally sustainable and energy efficient ports.