quits her job to pursue something more adventurous. She speaks fluent English and intersperses English expressions even while speaking Korean with her teammates. Nam Do-san's family Kim Hee-jung as Park Geum-jung Nam Do-san's mother. Kim Won-hae as Nam Sung-hwan Nam Do-san's father. Jang Se-hyun as Nam Chun-ho Nam Do-san's cousin. SH Venture Capital Seo Yi-sook as Yoon Seon-hak The CEO of Sandbox and SH Venture Capital. Kim Min-seok as Park Dong-cheon The assistant or secretary of Ji-pyeong and mentoring manager of Sandbox's 12th batch. Others Jasper Cho as Alex Kwon One of the mentors at Sandbox's 12th batch and the owner of 2STO, a Silicon Valley company. Kang Yoo-seok as Shin Hyeon A computer programmer, Shin Jeong's twin brother. Joo Bo-Young as Shin Jeong A computer programmer, Shin Hyeon's twin sister. Kim Ji-in as Seo-hyun Special appearances Kim Joo-hun as Seo Chung-myung (ep1) Seo Dal-mi's and Won In-jae's father. Having had enough of being degraded at work, he decides to start his own business, which leads to his divorce and after a year, he manages to get a deal and it is implied that he inspired the name "Sandbox" during a chat with the owner who happens to be the current "Sandbox" CEO Yoon Seon-hak. On the very same day, while going home he dies in the bus due to brain injuries from an earlier car accident. Yang Dae-hyuk as Yoon Byung-soo (ep9-10) Yeo Jin-goo as Jang Young-shil (voice) / Hong Ji-seok (ep16) Lee Bo-young as woman at pub Moon Se-yoon as security guard Park Chan-ho as Nam Do-san's favorite baseball athlete Bae Hae-sun as Lee Hye-won, team leader at Seonju Life Insurance. Original soundtrack Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7 Part 8 Part 9 Part 10 Part 11 Part 12 Part 13 Part 14 Part 15 Part 16 Part 17 Episodes Reception Critical reception The South China Morning Post ranked it #10 on its list of "The top 10 K-dramas of 2020". Kim Jae-ha of Teen Vogue including it on the list of the "11 Best K-Dramas of 2020" said that "Start-Up reinforces the idea that no matter how fractured a family is, the ties remain – for better or worse" . Viewership The series logged 4.5% in viewership rating for its first episode. Adaptation In March 2022, it was announced that GMA Network will produce a Philippine adaptation of the