["Journal of Consumer Behaviour, EarlyView. ", "\nABSTRACT\nThe study examines the dilemma faced by consumers in balancing the concepts of sustainability and luxury in the context of self‐gifting. The research is based on the Affect‐Behavior‐Cognition (ABC) framework and the Consumer‐Brand Identification (CBI) theory, which seeks to understand how the perceived sustainability–luxury fit and brand ethicality influence emotional reactions and consumer behavior after purchase. A mixed‐methods design with two phases has been employed. The first phase consists of extensive interviews with participants from three countries: India, the UK, and Australia. In the second phase, we verified a conceptualized model using surveys with 470 consumers, employing confirmatory factor analysis and structural equation modeling. The results highlight that a fit between sustainability and luxury, as well as brand ethicality, can enhance sustainability‐induced brand attachment and eco‐luxury pride, which in turn drive self‐gifting intentions, post‐purchase impact actions, electronic word‐of‐mouth, and consumer well‐being. Brand transgression history deteriorates, whereas long‐term orientation reinforces these affect–behaviour relationships. Thus, besides managerial implications, the study advances sustainable luxury theory by positioning sustainability as an emotional and identity‐based driver of consumer behaviour through the integration of the ABC and CBI frameworks.\n"]