Journalists subsequently accused the show`s producers of sensationalizing the young soprano`s background as a "sob story," engineered to play on viewers` sympathy for the sake of ratings.
"The reason I told that story on the show wasn`t because I was told to by producers. I told my story of being a victim of bullying because I believed it would help people who were going through what I had gone through be stronger," Johnston told The Korea Herald in an email interview.
Johnston was ostracized by his peers for his love for singing and having a "girly voice."
"That bullying was really a bad thing, so sometimes it`s too hard for me to remember those days and experiences, but I`m also not really uncomfortable with media which covers my stories. Rather, I`m glad that I could give courage to people like me," he said.
"For me, singing is such an amazing thing and it may be the only thing that I want to do throughout my life. It`s the only thing that I`m good at. So it`s like almost everything to me."
Simon Cowell signed the young singer to his label after the show`s season wrapped last year.
Cowell, in addition to being one of the panel judges, also produces the British talent show. Johnston`s debut album "One Voice" was released last September on SyCo Music -- Cowell`s division of Sony BMG.
"People say he`s really nasty on the telly (TV) but all he does is says what he thinks. But he`s normally always right because he`s really professional at what he does and he`s a really nice man behind the scenes and also in the recording studio. He`s been giving me everything I need," he said.
Not one to be dismayed by the naysayers and cynics attempting to extinguish the spark in his career, the Johnston said he just simply "carries on singing," when faced with criticism.
"When I was around six years old, I was just singing in an assembly and my teacher, Kim Harris, went out to me on the same day, and said to me `You have a pretty voice, why don`t you try out singing in Cathedral?` and I said yes. So that`s how it all started."
It was after this meeting that the singer would join the Carlisle Cathedral Choir and later became the head chorister.
"If I have a chance, I would like have duets with singers like Andrea Bocelli, Placido Domingo and Paul Potts. They are my heroes but I know I have to wait, because my voice needs to become more mature. So till then, I`d like to work hard to and take every necessary step to get to work with them in the future."
By Song Woong-ki