Supporting
Ha Jun as Seon Woo-jin (special appearance)
Kim Seo-joon as teen Woo-jin
Tae-hyung's older brother. He placed Tae-hyung in an orphanage as a child to protect him from their father, Gyu-tae, though he kept this motivation a secret. After reuniting with Tae-hyung years later, he struggles to explain his past actions. He dies in a car accident shortly after learning of his father's release from prison, leaving behind his son, Woo-ju.
Park Ji-hyun as Woo Hyun-ju (special appearance)
Park Sharon as teen Hyun-ju
Hyun-jin's older sister and legal guardian following the death of their parents. She spent her youth supporting Hyun-jin, even delaying her marriage to ensure her sister's stability. After marrying Woo-jin and having a son, Woo-ju, she continued to provide a home for Hyun-jin. She dies in a car accident alongside her husband, leaving Hyun-jin to care for her son.
Oh Hyun-joong as Kim Ui-jun
Tae-hyung's close friend and the owner of Milky Way Studio, a photography business specializing in infants. He met Tae-hyung in a school photography club where they bonded over their interest in film photography. As the only person aware of Tae-hyung's family background, he provides emotional support and a private space for Tae-hyung to discuss his personal difficulties.
Oh Se-eun as Ye-eun
Hyun-jin's college classmate and close friend.
Kang Ae-shim as Park Ae-ja
Hyun-jin and Tae-hyung's neighbor who lives with her son, Doo-sik. Known for her generosity and knowledge of the local residents' lives, she provides emotional support and practical childcare assistance to Hyun-jin and Tae-hyung as they adjust to raising their nephew.
Kim In-kwon as Bae Doo-sik
Hyun-jin and Tae-hyung's neighbor and Ae-ja's son. A self-appointed supervisor of the villa's maintenance, he frequently involves himself in the affairs of other residents. Although his efforts to help often lead to complications, he is a dedicated caregiver to his mother. He frequently speculates about the nature of the relationship between Hyun-jin and Tae-hyung.
Han Ji-hyo as Kim Ji-hyun
Hyun-jin and Tae-hyung's neighbor and a social media influencer known for her childcare and baby food expertise. As an experienced mother of three, she acts as a mentor to Hyun-jin, offering practical advice on raising Woo-ju. She also uses her influence within the local daycare community to support Hyun-jin and address neighborhood rumors.
Lim Sung-jun as Lee Jae-min
Hyun-jin and Tae-hyung's neighbor and Ji-hyun's husband. Despite his reserved exterior, he is a family-oriented man who assists his wife in raising their three children. He works as a delivery driver and occasionally checks on Woo-ju's wellbeing while interacting with Hyun-jin and Tae-hyung.
Jin Seo-yeon as Amy Chu (Chu Ui-jeong)
A prominent and temperamental fashion photographer known for her perfectionism and artistic rigor. She traditionally handled all her professional work with only her husband, Mu-saeng, acting as her manager. Following Mu-saeng's request for a divorce, she hires Tae-hyung as her first formal assistant. Despite initial friction over his bold personality, she acknowledges his technical skill in executing her creative concepts.
Ku Sung-hwan as Jo Mu-saeng
Amy's husband and long-time manager. For 15 years, he managed every detail of Amy's professional and personal life, adopting a specific aesthetic to meet her standards. Seeking independence, he initiates divorce proceedings and recruits Tae-hyung to replace him as Julia's assistant. Despite his desire to leave, he remains protective of Amy's reputation and experiences jealousy regarding her professional bond with Tae-hyung.
Yun Woo as Oh Seung-taek
A junior photographer who views Tae-hyung as a mentor and role model. They became friends while working together as assistants at Oh Film. Though initially confused by Tae-hyung's decision to shift careers and take on childcare responsibilities, he continues to support him. He eventually gains a position at Film Pluto through Tae-hyung's recommendation.
Choi Gyu-ri as Baek Se-yeon
Hyun-jin's close friend from college and a member of the Public Relations Team at BS Food. Coming from a wealthy background, she provides a carefree contrast to Hyun-jin's pragmatic personality. She acts as a confidante for Hyun-jin, assisting her with career challenges and childcare. She frequently observes and comments on the romantic tension between Hyun-jin, Tae-hyung, and Yoon-seong.
Kim Seong-jeong as Jo Gyu-jeong
A member of Planning Team 3 at BS Food and Yoon-sung's assistant. He prides himself on being Yoon-sung's primary supporter and relies on his social skills to navigate the competitive corporate environment. Although he initially feels threatened by Hyun-jin's competence and her rapport with Yoon-sung, he eventually provides her with occasional assistance.
Chun Yi-seul as Kim So-hee
The senior member of Planning Team 3 at BS Food. Unlike her workaholic colleagues, she prioritizes a work-life balance and dislikes working overtime. Although she is initially annoyed by Hyun-jin's excessive enthusiasm, she eventually warms up to her as Hyun-jin's competence helps reduce the team's overall workload.
