The Importance of Ethics in Organisations, Their Leaders, and Sustainability

In modern organisations, ethical leadership has emerged as a key driver of sustainability, shaping both employee behaviour and long-term organisational performance. This study investigates the mechanisms through which ethical leadership fosters organisational sustainability, with a focus on the mediating role of organisational commitment. A quantitative, cross-sectional survey was conducted in mainland Portugal between January 2024 and January 2025 with a sample of 285 employees from medium and large companies (48% male, 52% female). Ethical leadership was measured with the 10-item Ethical Leadership Scale (α = 0.94), organisational commitment with a 7-item validated scale (α = 0.91), and organisational sustainability with a 12-item scale capturing ethical climate and voluntary pro-environmental behaviours (α = 0.93). Data were analysed using structural equation modelling with maximum likelihood estimation and bootstrapping. Results support the hypothesised model, showing that ethical leadership positively predicts organisational commitment (β = 0.62, SE = 0.07, p < 0.001, 95% CI [0.48, 0.75]) and organisational sustainability indirectly through commitment (indirect effect β = 0.31, SE = 0.06, p < 0.001, 95% CI [0.20, 0.43]). Direct effects of ethical leadership on sustainability were weaker and non-significant once the mediator was included, confirming the centrality of commitment. Model fit indices indicated strong adequacy (CFI = 0.962, TLI = 0.954, RMSEA = 0.048, SRMR = 0.041). Theoretically, the findings reinforce the integration of ethical leadership theory with sustainability research, clarifying the role of commitment as a mediating mechanism. Practically, the study suggests that fostering ethical leadership behaviours—fair decision-making, role modelling, and integrity—can strengthen employee commitment, which in turn drives sustainable organisational practices. This highlights the importance of leadership development programmes centred on ethics as a strategic lever for long-term sustainability.