S eo Jung-jin is a pioneering South Korean pharmaceutical entrepreneur and the founder of Celltrion, a biopharmaceutical company that has become a global leader in the development of biosimilars. Unlike many of South Korea's billionaires who inherited wealth from family-run 'chaebols,' Seo is a self-made man. He began his career at Daewoo Motors, but after the company collapsed during the Asian financial crisis, he found himself unemployed. With a small group of colleagues, he decided to venture into the nascent field of biotechnology.

In 2002, he founded Celltrion, initially as a contract manufacturing organization for biologic drugs. Seo's vision, however, was to develop biosimilars—near-identical copies of complex biologic drugs that have come off patent. This was a high-risk, high-reward strategy that required immense investment in R&D and navigating complex regulatory approvals. His bet paid off spectacularly when Celltrion's Remsima, a biosimilar of Johnson & Johnson's Remicade, became the world's first monoclonal antibody biosimilar to be approved by the European Medicines Agency. This success catapulted Celltrion to the forefront of the global biosimilar market and made Seo one of South Korea's richest individuals.