She crosses paths with Park Dong-hoon (Lee Sun-kyun), a man carrying deep personal wounds and grappling with betrayal, workplace mistreatment, and the heavy responsibility of his family.

On November 8, 2017, news outlets reported that Lee Sun-kyun and IU would play the leads in My Mister, directed by Kim Won-seok of Misaeng and Signal, and written by Park Hae-young of Another Miss Oh.

[16] Both tvN and IU's agency commented that nothing had been finalized;[17][18] the main cast was confirmed on November 13 with the addition of Oh Dal-su and Song Sae-byeok as Lee Sun-kyun's character's brothers, and Na Moon-hee as the mother of the three.

[19] IU accepted the part of Lee Ji-an because she was interested in working with director Kim Won-seok and because the silent, tense role differed from the cheerful and cute characters she had previously portrayed.

The Korea Communications Standards Commission commented that a number of complaints had been received and that it was checking them,[33][34] while the production team replied that the complicated relationship between the two characters would be resolved gradually and to be patient.

"[36] Real News instead observed that the first two episodes had managed to demonstrate the intention of depicting the process of mutual understanding between characters of different generations and genders who were at odds with each other,[37] while pop culture critic Jung Deok-hyun called My Mister "a survival thriller.

[48] Huffington Post Korea and Sports Hankook wrote that it talked about the meeting of broken people of different ages and genders, blurring the lines between the many barriers of today's society and showing how human solidarity led to demolishing one's walls and discovering that the world was a warmer place than expected.