Historically, primary human progenitor cells (e.g., WI-38 and MRC-5 diploid-cell sources) have been industrially applied in research and in manufacturing processes for vaccines and for biologicals. Furthermore, tissue-specific primary progenitor-cell banks have recently been developed and exploited for the provision of safe, consistent, and effective cellular active pharmaceutical ingredients (API) in homologous allogeneic regenerative medicine applications. Notably, the modern legal and regulatory frameworks for novel therapeutic products and for progenitor-cell therapy development have been iteratively optimized to guarantee utmost product safety, quality, and efficacy. Over 50 years of global technical hindsight around progenitor-cell biotechnological substrates and over 30 years of in-house clinical experience around the therapeutic uses of standardized progenitor-cell sources in Switzerland have demonstrated the importance of such biological materials for public health. The aim of this entry work was to summarize the evolution of the industrial applications of selected primary progenitor-cell sources, ranging from the use as robust biotechnological substrates to standardized cellular API manufacture and their clinical uses in highly specialized regenerative medicine.