The research explores how Swedish apparel companies are integrating Circular Economy (CE) principles into the product design phase and identifies Critical Success Factors (CSFs) and Key Performance Indicators (KPIs) for circular and profitable apparel products. It uses a multiple case study approach, interviewing employees from five companies involved in the Vinnova project. Key findings include the importance of design for durability, balancing recycled content with quality, and the need for measurable CE principles. The study highlights the need for KPIs to track circular design performance and suggests managers prepare for upcoming EU ESPR legislation. Limitations include its focus on Swedish companies and the short research timeframe. Future research should further explore the impact of ESPR and develop more KPIs for CE in the apparel industry.