This study examines the influence of Green Human Resource Management (GHRM) practices on organisational sustainability based on survey data from 159 respondents (39 managers and 120 employees) across five service industries in Saudi Arabia. Data were analysed using a multi-level design and hierarchical linear modelling. Findings show that GHRM practices directly enhance sustainability through structural pathways such as recruitment standards and certification, while employee eco-friendly behaviour (E-EFB) partially mediates the link between GHRM and organizational sustainability. The observed E-EFB partial mediation mechanism integrates the Ability–Motivation–Opportunity (AMO) and Social Identity perspectives, as it demonstrates the concurrent operation of behavioural and structural pathways under Saudi Vision 2030. Moreover, presenting evidence from service industries in Saudi Arabia extends prior research in the Gulf Corporation Countries (GCC) beyond the manufacturing contexts. Practically, the study identifies high impact levers like training, performance reviews, and incentives programs that directly influence sustainability, as well as structural elements like certification and hiring. The study offers actionable insights for policymakers seeking to embed sustainability into organisational systems by linking outcomes to Sustainable Development Goals (SDGs 8, 12, and 13).