He's noted amongst fans for being the least scandalous member of One Direction.
We may now know why. It's been revealed the 22-year-old Irish singer had sued UK paper Express Newspapers (specifically Daily Star) over articles he claims defamed him.
In late July, a series of snapchat pictures showing Niall sitting in on a jam session featuring two other big name celebs - Justin Bieber and Cody Simpson - also appeared to show a table full of drugs in front of them.
A number of publications used these images to illustrate false stories about Horan, Bieber and Simpson using hard drugs. Or that's what the Infinity singer's lawyers are claiming, anyway.
A UK judge has agreed with them, stating the articles definitely imply drug use, by using suggestive language like "Niall was staring blankly" and repeatedly referencing US TV series Breaking Bad, a show about a drug dealer.
It is not yet know what, if anything, will happen to the tabloids that printed the story, but with a High Court judge on his side, it's apparent Horan has won this round against trashy mags using his name to make money via sensationalism.
Niall isn't the first 1D singer to take the media to court. In 2013, Harry Styles took the paparazzi to court and won. His success meant paparazzi could no longer pursue him by vehicle or camp out within 50 metres of his home. Like Niall, Styles also took Daily Star to court late last year, over a false report of a sexual photo published on their front page. The paper tried to recant the error, but Styles sued them anyway. It is not known how or if the case was settled.
Horan and Styles will attend and perform at the BBC Music Awards in the UK, along with the rest of 1D, on December 10.