 Sung-hoon invested in entertainment industry but has been involved in some messy legal battles for a few years.Finally, he put behind legal troubles and released a re-recording of the hit single "couple" in 2014.On June 12, 2015, Sung-hoon released 'Someone Make Me Laugh' for SBS weekend drama ‘Divorce Lawyer In Love’ OST

On February 20, 2016, Sung-hoon held small Concert "The Fifth Season" in Seogang University, Mary Hall Grand Theatre; tickets were reportedly sold out within one minute.