Case Company L is a brand collection company owning 6 clothing brands, namely MiaMia, MoNoSpace, WOOxWOO, Pesaro, Gina Su, and Kelly’s Handmade Dress. These brands boast unique characteristics, allowing Case Company L to provide consumers with all types of clothing products rather than unified commodity. In this study, the management team of Case Company L was interviewed for a case analysis on its business model as a designer brand, providing a reference for future clothing businesses. Unlike other clothing companies, Case Company L uses designer brands to reinforce its apparel characteristics; with a strong relationship with customers, effective team management, and favorable sales and business strategies, Case Company L has successfully grown in the face of various challenges.