Supporting
Jang Young-nam as Kim Ok-hee, the twins' mother and an elementary school lunch lady. She is a strong-willed single mother who has been the head of her household for nearly 30 years. She favors Mi-rae.
Cha Mi-kyung as Kang Wol-soon, the grandmother of the twins and a former beauty salon owner. She helped with childcare and housework before suffering a stroke.
Moon Dong-hyeok as Song Gyeong-gu, the assistant manager of Kyunggu Mart, as well as Mi-ji's ex-boyfriend and current best friend.
Yoo Yoo-jin as Park Ji-yoon, a high school friend of Mi-ji and Mi-rae.
Im Chul-soo as Lee Chung-goo, Lee Ho-soo's senior colleague and a highly capable lawyer known for his impressive win rate.
Kim Sun-young as Yeom Beon-hong, Lee Ho-soo's mother and vice principal of an elementary school. She has been a long-time neighbor of the twins' family in Duson-ri.
Shin Jeong-won as Hwang Ji-soo, Lee Ho-soo's secretary at Wongeun Law Firm.
Jeong Seung-gil as Choi Tae-gwan, director of the Planning and Coordination Bureau.
Lee Si-hoon as Shin Gyeong-min, head of the Planning Strategy Team.
Go Ae-ri as Ahn Mi-jung, a member of the Planning Strategy Team.
Yang Dae-hyeok as Hwang Yun-ho, a member of the Planning Strategy Team.
Sim So-young as Lee Hyo-kyung, a member of the Planning Strategy Team.
Hong Sung-won as Kim Tae-yi, a data analyst.
Park Ye-young as Kim Soo-yeon, a former member of the Planning Strategy Team.
Nam Yoon-ho as Park Sang-young
Jung Eun-pyo as Jo Myeong-gap, president of the Duson-ri Youth Association.
Kim Kyung-duk as Kong Il-nam, a shopkeeper at Seedong Market and a Youth Association member.
Won Mi-kyung as Kim Ro-sa/Hyeon Sang-wol:
Moon Su-a as young Hyeon Sang-wol.
Kim Do-eun as child Hyeon Sang-wol, the owner of Ro-sa's Restaurant, who is diagnosed with dyslexia.
Park Hwan-hee as Kim Ro-sa:
Kim Tae-yeon as child Kim Ro-sa, a poet who graduated from Seoul National University.