The pint-sized Mullingar star, who has eight million followers on Twitter, returned to where it all began and performed at the Manchester Arena with his bandmates at the finale last weekend.
Mum Maura was backstage with her partner Chris Gallagher as they joined the 10,000-strong crowd cheering him on.
A few months ago, Niall's mum moved to London so she could be closer to her son as he continues his stellar ascent up the showbiz ladder.
However, fans hoping to rub shoulders with Niall at the after-show party were disappointed after he and his bandmates hopped on their coach back to London as soon as the winner was announced, with only Louis Tomlinson staying behind.
The VIP party took place at the luxury Lowry hotel in Manchester. X Factor judge and Mayo man Louis Walsh enjoyed a rare night on the tiles and was spotted with a victorious Nicole Scherzinger. They celebrated until the small hours with winner James Arthur.