Hartnett, who rose to fame with roles in films including Black Hawk Down and Pearl Harbour, was asked to play the Man of Steel in three prospective Superman films.
However, after the release of Pearl Harbour in 2001, Hartnett turned increasingly towards independent projects, and has spent the past decade working outside of the Hollywood mainstream.
Speaking to Mr Porter, Hartnett said: “The guys who are on top are terrified that someone’s coming up behind them. If that’s your real ambition, to be on top all the time, you’re going to spend your whole life looking over your shoulder.
“I never wanted that. I want to do good work with people I like and spend my free time with people I care about.”
The role of Superman, which Hartnett turned down, was eventually given to Brandon Routh instead, for the 2006 film Superman Returns.
“At the time, it was so obvious to me to turn it down,” said Hartnett. “I was being offered movies by the very top directors, and Superman was a risk.
"Yes, there was a lot of money involved but I didn’t think that was the be-all and end-all. People thought I was crazy for not chasing that brass ring a little harder but I felt completely comfortable being with the people I knew liked me before I was making films.”
Hartnett has three children with his partner, St Trinian’s actor Tamsin Edgerton.