Paul is one of two brothers (the other being Phil Hartnoll), who made up the electronic band called Orbital. He was born on 19 May 1968, in Dartford, Kent.

The Ideal Condition is the solo album that Hartnoll released in May 2007. There is a more acoustic lean on this album than on Orbital's past albums because that's how he thought it would work best. Hartnoll decided (with the help of Arranger Chris Elliot) to have the album played by a union-full orchestra which is a totally different direction than Orbital would have taken.

After Orbital's second and final breakup in 2014, Paul went back to the studio as a soloist again, this time under the name 8:58. He promptly released a self-titled debut album. The album's first single "The Clock" features English actor Cillian Murphy on vocals.

Paul announced on his blog in July 2015, he would be dropping the 8:58 moniker and go with his given name Paul Hartnoll once again.