"Right off the bat, it was always quite a brutal experience," he says.
"On our first day, on the pilot, I got six stitches from a stunt gone wrong. We shot for another six hours in freezing creek water, then they took me to hospital, stitched me up and sent me back to work at 6am. That was a sign of things to come."
The show's been lauded for its Tarantino-times-10 action scenes, which are a point of pride for its star.
"One reason the stunts look as good as they do is that we rarely used stunt doubles. They preferred the actors to do it unless someone could get really hurt. So a lot of time went into rehearsing and choreography, and that meant they could use a lot more of the footage than you can with stunt doubles. They didn't have to cut around the stuntmen's faces." So, if the fights look real, it's because they are.
Stitches and bruises notwithstanding, playing the lead on a top-shelf US series must be very different from working on the local Outrageous Fortune where Starr made his name in the double roles of twins Jethro and Van West.
He agrees it is different: he has to work a lot harder.
"The biggest difference is the hours," he says. "Americans live to work and Kiwis work to live. All of a sudden I found myself looking down the barrel of regularly doing 12 or 15 hours a day. I remember thinking 10 hours was a long day in New Zealand."
The production had to invent a new day of the week to accommodate their schedule: "We ended up doing 'Fraturdays' to maintain the schedule, starting early on Friday and ending up early Saturday morning."
Indeed, the popular image of the Starbucks-slurping, shih-tzu-walking Hollywood star is a long way from the humdrum, hardworking reality. There's no time for diva dramatics. And acting is acting wherever you are.
"It's the same deal," says Starr. "It's a different surface but it's like moving from grass to clay in tennis. The ball might bounce a little higher and you adjust how you're playing but it's the same sport.
"There is more emphasis on the cast over here. You're the centre of the vortex, and the potential is there to get more attention.
"You could exploit that, depending on the sort of person you are. I know people do, but people from New Zealand are grounded. I put a reasonable amount of effort into making sure we had a good environment on set -- I've been on some sets where the crew aren't allowed to talk to the cast. That's not the kind of environment I want to work in."
He's not sorry the show has come to a natural end and avoided prolonged death throes. I won't mention names but there are a few shows around now that are past their sell-by date.
"We were very conscious of that. [Co-creator] Jonathan Tropper loved it and really enjoyed making it. But he was loathe to let it get kicked around two seasons too long and lose the momentum it had. We didn't want it to be remembered as something that was good at one point.
"The story he wanted to tell was always about this guy and the love story, and once that felt completed it would have been a case of looking for stories.
"The story of Lucas Hood felt pretty well wrapped up, so it was a good time to go out."
In fact, Lucas comes full circle by the show's last episode. "He rode in on a motorbike and he rides out on a bike, but a huge internal shift has gone on. He came in restless and lost and when he leaves he's more grounded and accepting of himself as an imperfect animal. There is a sense of acceptance."
Apart from Lucas and the love story, the show has Amish folk, neo-Nazis, Native Americans -- are there a few undercurrents there that make it more than "just" an action show?
"Definitely in the writers' heads," says Starr. "But I don't think there was any preaching - just some observations about the way things are over here, and people could take or leave them if they wanted to. We literally had cowboys and Indians in season three: read into that what you will."
His focus was always firmly on his own character. "He'd had a pretty traumatising experience and was struggling to cope in the world. Seasons one to three were about him confronting the world and trying to find his place and largely failing. But the lead can't succeed or there's nowhere to go."
Until the final episode.
Now, Starr has new projects under consideration. "I don't feel panicked about working again. [Before Banshee] I knew things would come along. It was just a question of being patient and relaxing into it. I've got a couple of other things I'm collaborating on, but I don't feel that nagging impatience to get work immediately."
Banshee, series 4, screens on The Box, Thursdays, 9.30pm
