He was one of the four MCs on the Radio Star segment of Golden Fishery on MBC and band mate Kyuhyun took over for him when he enlisted and Secret of Saturday Freedom on KBS.
On 1 September 2011, Kim enlisted for his mandatory military service. He is serving as a public service worker for 23 months, after undergoing four weeks of basic training at the Nonsan military camp in Chungcheongnam-do Province.
On 27 September 2011, the single "Breakups are So Like Me" by Kim Jang-hoon was released, which featured Heechul, who also starred in the music video. It was completed the day before his enlistment, hence his parts during the performance on Music Bank and Show! Music Core, was filled in by bandmates, Yesung, Eunhyuk and Shindong, who performed with Kim Jang Hoon.