Based on a novel by "Mystic River" author Dennis Lehane, the 1950s psychological thriller is the fourth film pairing Scorsese with DiCaprio, after "Gangs of New York" (2002), "The Aviator" (2004) and the Oscar-winning "The Departed" (2006).
"Each experience has been unique. It's been a progression, now it's been 10 years," DiCaprio, 35, said at a news conference with the director as their new film premiered out of competition in Berlin.
The two heaped praise on one another, with DiCaprio saying "the biggest gift that he's given meis an appreciation for cinema and cinema's history, and an entirely new perspective on my view of this art form."
"I grew up on his work, really," he said. "As a younger actor, you'd be a fool not to jump at the opportunity to work with somebody who I consider and many consider the definitive director of our time."
The 67-year-old director, for his part, said working with DiCaprio has lead to a special relationship.
"Trust is really the key" and was built up over time, Scorsese said, adding that they "really reached a kind of comradeship in 'The Departed.'"
"I see him as a young man developing as a wonderful actor," he said. "I'm very happy to be around when this is happening with somebody with such extraordinary talent, to be able to focus that and perfect it."
"Shutter Island" also stars Ben Kingsley, Patricia Clarkson, Mark Ruffalo and Michelle Williams. It is set in 1954, a time of Cold War paranoia, when Scorsese himself was growing up.
It follows the investigation into the disappearance of a murderess from a mental institution on an island. DiCaprio plays a U.S. Marshal in Boston looking for the woman, and his involvement in the case starts to make him question his own sanity.
"This was a complex jigsaw puzzle of emotional back stories and dream sequences and truth and fiction," DiCaprio said. "It was challenging and fulfilling."
Scorsese said he was attracted to the material in part "because it's set in the 50s and because of the tone of fear and paranoia and secrecy and trauma."
"I grew up during the 50s, I grew up during the Cold War, I grew up expecting air raids every day," he said. "That's what we were told."
Scorsese and DiCaprio may not be done collaborating yet.
"We're always talking about different projects," DiCaprio said. "If I'm lucky enough to work with him, I would consider it a gift."