TV Legally Dad Legally Dad 4/10 by 15 users Orphan Ah Young is a financially struggling 23-year-old who takes care of her 8-year-old sister Dan Bi while juggling part-time jobs. One day a 28-year-old man Yoo Sang appears in front of Ah Young offering to be her dad through a signed agreement. Details Casts Posters Images Title Legally Dad Alternative Titles Step Dad On Paper, Dad by Documentation, 서류상 아빠 First Air Date 2020-08-27 Last Air Date 2020-10-01 Number of Episodes 6 Number of Seasons 1 Genres Drama, Networks , Casts Lee Hyun-joo, Choi Kyung-hoon, Lee A Ra, Min Se Woong, Kwon Hae Woo Plot Keywords , Kim Ah Young Lee Hyun-joo Sul Yoo Sang Choi Kyung-hoon Kim Dan Bi Lee A Ra Yoon Joo Ho Min Se Woong Yoon Hae Woo (Yoo Sang's Secretary) Kwon Hae Woo