"My instinct was that he had somebody else in mind, which turned out to be Viggo (Mortensen)," Crowe said. "He should be allowed to hire the actor that he wants."
The movie went on to rake in more than $US860 million worldwide, and Crowe would likely have received at least $100 million if he'd starred in the film.
"Do you think about that every day?" Stern asked Crowe. "Do you ever say, 'I could have had $100 million?'"
"Never thought about it. Only in situations like interviews where people are polite and kind to add sh*t up for you," Crowe joked.
In the interview with Stern, Crowe was also asked about his decision to pass on playing Wolverine in the 2000 X-Men movie.
"Even if I'd done the film, I wouldn't have carried it through with the grace and the direction that Hugh (Jackman) gave it," Crowe said.
The actor previously opened up to Nova's Fitzy and Wippa about why he passed on playing the mutant superhero, explaining it had something to do with his role in Gladiator.
"If you remember, Maximus has a wolf at the centre of his cuirass, and he has a wolf as his companion … which I thought was going to be a bigger deal (at the time)," he told the radio hosts in 2017. "So I said no because I didn't want to be 'wolfy', like 'Mr Wolf'."
But it turned out the whole drama was over nothing — most of Crowe's symbolic "wolf moments" in Gladiator were left on the cutting room floor.
"When Ridley (Scott, director) was cutting the movie, it was inconvenient to keep the dog alive — so the whole wolf thing, no one ever mentions it!" Crowe said.
Crowe was the one who encouraged X-Men director Bryan Singer to hire Jackman to play Wolverine, and Jackman has been incredibly grateful ever since.
"I owe (Crowe) him because two of the biggest roles I've ever had in my life he turned down — and suggested me for them," Jackman told EW.
"On X-Men, he was Bryan Singer's first choice for Wolverine, and he mentioned me also for (Baz Luhrmann's) Australia. He really is incredibly smart, and generous."
