Season 1 of Family by Choice premiered on October 9, 2024.

Despite not being biologically related, Kim San-ha, Yun Ju-won, and Kang Hae-joon share a close bond with each other. The trio spent their adolescence raised by Ju-won's father Jeong-jae and San-ha's father Dae-uk, who did their best to give them a happy childhood as they healed from past trauma. Upon reaching adulthood, however, San-ha and Hae-joon sought out their biological families, leaving Ju-won behind. Ten years later, the five members of their found family reunite, but things aren't the same as they used to be. Ju-won holds some resentment after feeling abandoned by San-ha and Hae-joon, while the two boys are struggling with new romantic feelings for Ju-won and their own familial issues.