The 21-year-old triumphed over Andy Abrahams and Journey South in a close final which saw viewers cast more than 10.8 million votes.
Just 1.2% separated Shayne from Andy, who finished in second place. He had been bookies' favourite for most of the series, despite a highly public drama that saw his mentor Louis Walsh temporarily quit the show.
Shayne's debut single, 'That's My Goal', will be released on Wednesday.
Click here to read Dek's verdict on the finale