The present study was conducted with the aim of designing and validating an optimal model of brand identity in the Iranian apparel industry. In terms of approach, the study adopted an exploratory mixed-methods design and was implemented in two qualitative and quantitative phases. In the qualitative phase, data were collected through semi-structured interviews with 16 managers and experts in the apparel industry using theoretical sampling. The qualitative data were analyzed based on Strauss and Corbin’s grounded theory method with the aid of MAXQDA 24 software. In the quantitative phase, a researcher-made questionnaire developed on the basis of the qualitative findings was distributed among 384 customers of the apparel industry, and the resulting data were analyzed using the partial least squares method in Smart PLS software. The findings showed that brand identity in the Iranian apparel industry is a multidimensional and context-dependent phenomenon shaped by product quality-building and trust-generating capabilities, the cultural–identity capital of the brand, institutional trust and the brand accountability system, and the capacity for innovation and value creation. Moreover, the sociocultural conditions of Iranian consumption, governmental support, and structural and competitive challenges play an effective role in directing strategies for strengthening and reconstructing brand identity. The results of model evaluation also indicated the favorable fit of the proposed model; accordingly, the GOF value was 0.626, RMS_theta was 0.106, SRMR was 0.055, NFI was 0.677, and the normed chi-square value was 1.589. The innovation of the study lies in the fact that it does not explain Iranian apparel brand identity merely at the level of visual elements, advertising communications, or consumers’ mental image; rather, it conceptualizes it as a multilevel and indigenous construct linked to product quality, cultural meanings, institutional trust, supply-chain transparency, innovation, supportive policies, and the historical perception of Iranian-made goods. The theoretical contribution of the study is the provision of a native framework for understanding brand identity within the specific context of the Iranian apparel industry; a framework that integratively explains the strategic, cultural, institutional, experiential, and competitive dimensions of the brand. From a practical perspective, the proposed model can also provide a basis for rebuilding public trust, strengthening the identity-based differentiation of domestic brands, improving the image of “Made in Iran,” and enhancing the competitiveness of the Iranian apparel industry in domestic and regional markets.