The frequent consumption and discarding of clothing are unsustainable. Some minimalist practices in fashion can reduce fashion waste and the cost of carbon, one of them is the practice of capsule wardrobes. To support the sustainable practice of capsule wardrobe, we designed Minnie, the Musical Clothes Hanger — Minnie for short. Minnie is designed to help people who want to build a capsule wardrobe or other form of minimalist practice in their wardrobes. Applying the method of Research through Design (RtD), we investigate how people perceive minimalist lifestyles and reflect on Marie Kondo’s minimalist wardrobe practices. Based on the design research, we formed the appearance design, system design, and sound interaction design of Minnie. We propose that our study provides insights for designing artefacts to support minimalism in fashion.