All the songs by ECLIPSE, the fictional band created for this drama was sang by Byeon WooSeok himself. He took singing lessons to realize his role as idol Ryu Sunjae.
Byeon Wooseok did not know how to swim. He took swimming lesson for three months to realize his role as swimmer Ryu Sunjae.
According to a Soompi article (May 2024), "Lovely Runner" Ranks No. 1 On Viki For 6 Weeks + Achieves Highest Viewer Count Of 2024 Dramas.
The production of Lovely Runner was delayed three years. One factor holding back production was casting, as many actors rejected the role of Ryu Sun Jae.
Writer Lee Shi Eun, who is best known for writing True Beauty had actress Kim Hye-yoon in mind when writing the role of Im Sol. Both the director and writer have said the show would probably not be made if Kim Hye-yoon hadn't accepted the role.