In the era of sustainability in all aspects of business, fashion choices are not lagging. A motivated consumer focused on innovativeness holds the key to a sustainable future. This study evaluates the intricate dynamics of consumer innovativeness and its profound connection with preferences for sustainable fashion. Building upon the triple trickle theory, social cognition theory, and motivated consumer innovativeness (MCI) framework, this study investigates the relationships between distinct dimensions of innovativeness—functional, cognitive, and hedonic—and consumers' intentions to engage with sustainable fashion. Environmental concerns play the role of a mediator between the dimensions and purchase intentions. It applies established measurement scales using a sequential explanatory mixed method that integrates quantitative and qualitative phases. Partial least squares structural equation modeling (PLS-SEM) was used to analyze the proposed relationships. The results reveal a noteworthy impact of hedonic innovativeness on consumers' intentions to embrace sustainable fashion, mainly when environmental concerns act as a mediator. Positive relationships are observed between functional and cognitive innovativeness and consumers' purchase intentions. The qualitative study furthered the quantitative research findings by emphasizing the need for greater transparency from brands and targeted efforts in educating and expanding sustainable options. The outcomes highlight the considerable potential for businesses to encourage consumer acceptance of sustainable fashion by highlighting these products' inherent functional, cognitive, and hedonic advantages. Furthermore, it underscores the pivotal role of industry practitioners in educating consumers about the environmental impact of embracing a slow fashion approach.