Start-Up — Characters & Cast

Validating her late father’s life choices and building a transformative business that improves human lives.

Starts as a contract worker living in her sister's shadow. Through sheer grit, intuitive leadership, and relentless optimism, she learns the technical intricacies of tech development, endures the painful dissolution and rebuilding of her company, and emerges as a respected, fearless CEO.

Overcoming his chronic imposter syndrome to become someone truly deserving of pride and love.

Begins burdened by childhood fraud guilt (a stolen Olympiad math win) and running a failing garage company. Through Dal-mi's faith, hard lessons at Sandbox, and three transformative years at 2STO in Silicon Valley, he evolves into a mature, self-assured Chief Technology Officer who takes ownership of his talent.

Shielding Grandma Choi from heartbreak and proving his self-worth in a world where he started with nothing.

Rose from an impoverished orphan to SH Venture Capital's senior investment manager. Armored in sharp-tongued professionalism, his suppressed emotional world is unlocked through his devotion to Grandma Choi and unrequited love for Dal-mi. He ultimately achieves emotional maturity by letting go of Dal-mi, making peace with Do-san, and finding personal fulfillment through mentorship and social angel investing.

Achieving authentic success solely on her own merit, free from patriarchal corporate exploitation.

Appears initially as a pampered chaebol heiress, but reveals an acute awareness of being treated as disposable by her stepfather. She renounces her family privileges, enters Sandbox from scratch, builds Nature Morning/Injae Company, and reconciles with Dal-mi and her grandmother, legally restoring her original surname "Seo".