Radio Romance (TV series)

Song Geu-rim (Kim So-hyun) has always wanted to become a radio writer, but was forced to be an assistant writer as she lacks the writing skills. When her only show faces cancellation, she must secure her place as a writer and decides to try casting Ji Soo-ho (Yoon Doo-joon), a top star actor who is known to have a "perfect life".

• Yoon Doo-joon as Ji Soo-ho, a top actor who is accustomed to act based on scripts. He ends up becoming the DJ for a live radio show where nothing ever goes according to plan.^[7]
  • Nam Da-reum as young Ji Soo-ho
• Kim So-hyun as Song Geu-rim, the writer of Soo-ho's radio show with five years of experience as an assistant writer. She lacks writing skills but possesses excellent planning skills.^[8][9]
  • Lee Re as young Song Geu-rim
• Yoon Park as Lee Kang, the radio station's competent producing director. Because of his perfectionism, every program he handles achieved No. 1 in listener ratings.
• Yura as Jin Tae-ri, an over-the-hill actress who fell from grace due to a DUI accident that happened three years ago.^[10]

• Ha Jun as Kim Jun-woo (33 years old), Soo-ho's long-time manager who watches over every move of him.^[11]
• Kwak Dong-yeon as Jason, a 28-year-old psychiatrist who is Soo-ho's high school classmate and personal doctor.
• Oh Hyun-kyung as Nam Joo-ha, Soo-ho's 51-year-old biological mother who serves as CEO of JH Entertainment.
• Kim Byung-se as Ji Yoon-seok, Soo-ho's 55-year-old father who is a veteran actor.
• Seo Ye-seul [ko] as Jung Da-seul, a popular 23-year-old actress who has an affair with Soo-ho's father.
• Kim Ye-ryeong as Jo Ae-ran (53 years old), Geu-rim's mother who became blind during a surgery she had when she was 39.

• Kim Hye-eun as Ra Ra-hee, a 41-year-old radio program writer.
• Im Ji-kyu as Lee Seung-soo, a 43-year-old radio program director.
• Jo Byeong-kyu as Go Hoon-jung, a 30-year-old radio assistant director.
• Lee Won-jong as Kang Hee-seok, a 55-year-old radio station director.
• Yoon Joo-sang as Moon Seong-woo, a 57-year-old DJ of a thirty-year old radio program.

• Ryu Hye-rin as "Tornado"
• Shim Eun-woo as "Gamoom"
• Jung Yoo-rim [ko] as "Jangma"

• Jung Hee-tae as Ahn Bong-seob, a 37-year-old reporter.
• Choi Min-young as Woo Ji-woo, Soo-ho's friend who liked Geu-rim 12 years ago but died in a car accident.

• U-Kwon as Kang Minu (Ep. 1)
• Ji Il-joo as Oh Jin-soo (Ep. 2–3)
• Jung Gyu-soo as an amnesiac old man (Ep. 4)
• Bona as DJ Jay (Ep. 5)

Lead actors Yoon Doo-joon and Kim So-hyun first worked together in a 2014 advertisement. Yoon also made a cameo appearance in the 2016 TV series Bring It On, Ghost that starred Kim.^[12]

The series is a joint production of Urban Works Media (producer of the Bad Guys series) and Plusis Media (a subsidiary of the Sports Seoul [ko]-Seoul Shinmun group launched in 2017) for KBS.^{[citation needed]} The first script-reading of the cast occurred on December 19, 2017, at KBS Annex Broadcasting Station in Yeouido, Seoul.^[13]

On January 24, 2018, a photo was shared online saying that lead actress Kim So-hyun was shooting underwater. The photo shows a woman wearing a hanbok in the water on January 21. On that day, the lowest temperature was recorded below −16 °C (3 °F). During the press conference for the premiere of Radio Romance held on January 25, the drama's PD addressed online criticism regarding the outdoor water filming, despite the weather warnings. He issued an apology stating that "Kim So Hyun's outdoor water filming wrapped up on Sunday (January 21). We debated on it a lot, since she would be getting in the water. We ensured safety equipment nearby, as well as a camping car on set, and finished filming in the shortest amount of time possible. Due to time constraints, an action stunt double filmed additional outdoor water scenes yesterday (January 24). It was filmed by an action actor, not Kim So-hyun, wearing a winter suit and shot in a similar situation (January 21). The number of shots was done with one take and protection was taken right away. We apologize for causing concerns with this matter. The filming set is our life. Naturally, safety is important."^[14] At the press conference, Kim's hand was seen red.^[15]