On 11 February 2011 he won the third season of the Greek version of the television singing competition The X Factor after singing Joe Cocker’s "You Are So Beautiful".
He was awarded a two-year contract with Sony Music Greece.
Harry Antoniou (at times Charis "Haris" Antoniou) is the third Cypriot to have won the Greek competition, after Loukas Giorkas won in the first season and Stavros Michalakakos in the second season.
Working in his teens as a singer and saxophonist, he was able to attract more and more people creating its own fan club from a young age before applying to the Greek X-Factor.
He released his first digital single titled "Στον Κόσμο Μου Εγώ" with lyrics by Nikos Moraitis while preparing his debut album.