Kang heard about JTBC holding auditions for the second season of Phantom Singer and decided to apply. Of the 32 contestants who passed the preliminary screening, he was the only one without any formal training in singing or the performing arts. He sang "The Phantom of the Opera" for the televised audition in front of the panel of judges and sang Christine Daaé and the Phantoms parts himself in both the countertenor and his natural tenor registers. The video uploaded to Naver went viral immediately and garnered several million views by the final. Initially he commuted back and forth between Seoul and Busan during filming but ultimately took a year-long sabbatical from his job with the option of returning should Phantom Singer 2' not work out.