"This feeling of a solid marriage and fatherhood is better than I could've imagined. I'm happier now than I've ever been in my life."
Factor in trans-Pacific jetlag, and this guy could be excused for looking exhausted and sounding irritable, but quite the opposite, his vitality is palpable. "This time is always crazy," he says with that grin. "Two more weeks of this and then I'm playing golf again."
Damon’s respect for Greengrass, a former journalist who has brought a combination of searing realism and technical skill to films such as "Bloody Sunday" and "United 93", is clearly evident - he’s eager to work with him as much as possible.
"In every single project he has, I will be the first person in line to read it or to try and worm my way into it if I can," he says. "I think he brings out the best in all his actors. "United 93 was just incredible, and I thought the same of ‘Bloody Sunday’. He’s a major director, and he’s going to be around for a long time. He’s just a great storyteller.
"We were sitting in Deauville a few years ago on the Bourne Supremacy tour, doing a press conference, and we were by the pool and he started to talk about United 93. He literally laid out the film, which was incredible, and he later sent me a document which was his idea of how the film would be, and it was exactly how the film turned out. So he’s got this incredible ability to tell a story.
"He’s just one of these great storytellers who can spin a yarn for you that can leave you totally captivated, and he can translate that visually. I think there’ll be a lot more great movies coming from Paul, and I hope that I’m in them."
Unfortunately, a scheduling conflict exacerbated by the upcoming strike within the Hollywood film industry has forced Damon to pull out of Greengrass’s next project, the Iraq War drama "’Imperial Life in the Emerald City". Instead, the actor will reunite with "Ocean’s Eleven","Twelve" and "Thirteen" director Steven Soderbergh on the whistle-blower biopic "The Informant". While it’s another lead role for Damon, it’s not necessarily the kind of star vehicle that draws plenty of attention. He doesn't mind a bit.
"The role is usually the last thing I look at," he says. "I’m always looking at the director and the script first. What a lot of people think are virtuoso performances are oftentimes just parlour tricks and not really that challenging.
"To me, The Good Shepherd was unbelievably challenging - frame after frame of stillness and submerged anguish and all that stuff that’s underneath everything. I don’t mind that it was a very interior performance - I actually like performances like that. Creatively, that was a really fulfilling performance for me, and to work that closely with De Niro for months on end, to listen to him and learn about acting from him, right from the horse’s mouth...I can’t top that."