Became known as a member of the British-Irish boy band One Direction, who won a BRIT Award for "What Makes You Beautiful" in 2012. The band also won eight Teen Choice Awards in 2014. He released his debut single, "This Town," in 2016, followed by his solo album, Flicker, in 2017.
While growing up, he listened to Frank Sinatra and Dean Martin, and performed in Christmas productions with his school choir.
His group One Direction has won multiple Kids' Choice Awards for their albums Up All Night and Take Me Home.
His parents, Maura Gallagher and Bobby Horan, divorced when he was five; he has one older brother named Greg and a nephew named Theo. He began a relationship with Hailee Steinfeld in 2018. In 2016, he briefly dated Celine Vandycke.
He performed on the 2013 Take Me Home Tour with the other One Direction members: Harry Styles, Liam Payne, Louis Tomlinson, and Zayn Malik. Malik left the band in March 2015, and One Direction continued performing as a four-piece.