As consumers become more aware of and concerned about the environmental impact of their consumption choices, an increasing number of luxury brands are now engaging in sustainability practices. This study examines factors influencing the effectiveness of embedding sustainability in luxury brands. Specifically, the research focus is the effect of childhood socioeconomic status on moderating consumer preferences for sustainable (vs. regular, nonsustainable) luxury brands. Four experimental studies using different product categories and luxury brands show that preferences for sustainable (vs. regular, nonsustainable) luxury brands are stronger among consumers with relatively low (vs. high) childhood socioeconomic status (Studies 1–4). Notably, these preference patterns are driven by differences in the perceived importance of cooperation in the community among consumers with low versus high childhood socioeconomic status (Study 3). However, these divergent patterns are attenuated when consumption involves the nonluxury brand category (Study 2), and when consumers experience a high‐threat environment (e.g., the COVID‐19 pandemic; Study 4). As such, the findings of this study contribute to the literature by shedding light on the conditions under which consumers show preferences for sustainable (vs. regular, nonsustainable) luxury brands, establishing a theoretically grounded mediator (importance of cooperation in the community) and moderator (perceived environmental threat).