The article deals with the phenomenon of “private label” (PL) in the environment of retail chains and presents the methodology for its study. The evolution of this phenomenon is briefly described as a voyage of PLs from a sort of consumer perceived trade-off between price and quality towards converting them into competitive brands. Some features of PLs are noted that give them the opportunity to become mediators of a new culture of responsible consumption. Multidimensionality and complexity of representing the PL as a sustainability brand are shown, that leads to the need to apply an interdisciplinary approach to research and development of relevant curricula/courses. Understanding the function of a sustainability brand as a mediator of a new culture predetermines the need for a methodological approach based on the highest form of interdisciplinarity, viz. the transdisciplinarity. A conceptual model of sustainability branding for retail chains is presented, which considers additional factors that go beyond the seller-buyer interface: impacts of state and public institutions and consumer brand experiences, mainly accumulated in the respective online brand communities. The persistence of the problem of ensuring the adequacy of the semantic Russian-language terminological system of sustainability branding is emphasized. Possible practical applications of outputs of this work are proposed and directions for further research are outlined.