"But I'm not a raving lunatic," the new Knights coach tells the Newcastle Herald. "I will push the players' limits and yeah, they will have to work hard. We won't get anywhere if we don't. But at the same time, they will know I care about them.

"That's the important thing and I think you will do anything for someone who you know cares about you."

After signing off as assistant coach with the Sydney Roosters at the end of last week in the aftermath of the club's premiership win, O'Brien finds himself at the coal-face of one of the most challenging coaching jobs in the NRL.

He doesn't officially start getting paid by the Knights until November 1 but he's had no time off and says he won't be taking a break until Christmas. That won't surprise anyone who knows of his reputation for being a workaholic.

Talk to O'Brien, who spent more than a decade in the Melbourne Storm system under Craig Bellamy before joining the Roosters, for any length of time and you sense there is a real steel and tough edge to his character. Yet at the same time, humility is an important value he wants to instill right throughout the club.

"The biggest thing I take from my experience in Melbourne apart from the work ethic is the humbleness," he says.

"We are not better than anybody else. We're doing a job, just like the person down the road that works eight or nine hours a day laying bricks, fixing cars, cleaning hotels or whatever. We need to make sure we are humble.

"It comes back to the culture and having good people. We are serving the community, we are making them proud of us during the 80 minutes but also, we are part of the community - we don't sit above it. That's really important to me."

O'Brien is a country boy who was born in Goulburn and grew up in Batemans Bay where his dad was a local publican.

He started playing rugby league in the Under 8's when he was four, was a ball-boy for the Batemans Bay Tigers in Group 7 and almost from the moment he first laced on a boot, wanted to win a first grade grandfinal in his home town. He knows plenty about the passion of one team, one town clubs.

"I fell in love with representing the town," he says.

He played first grade at 17 and played under current Eels mentor Brad Arthur at one point before Arthur left for Cairns. O'Brien would have followed him too except "I couldn't leave without winning the grandfinal for the town first."

"I ended up linking back up with Brad in Cairns two weeks after we won the grandfinal in 2002." Eventually, it was Arthur who took him to Melbourne.

O'Brien first got his passion for coaching at Batemans Bay when he was playing first grade and coaching the Under 18's at the age of 23 with the help of a teammate. His side, which included a young Michael Weyman, made two grandfinals.

"We lost both but that's where I got the bug to want to coach," he says. "I parked it when I went up to Cairns to play for Brad for three or four years but was probably always going to come back to it."

When knee and shoulder reconstructions virtually ended his playing career, O'Brien followed Arthur to the Storm where he assisted with the club's Under 20's side.

It's doubtful any head coach in the history of the game has had a better apprenticeship than O'Brien. More than a decade at the Storm, firstly alongside Arthur and then directly under Craig Bellamy before a one year stint under Trent Robinson at the Sydney Roosters.

"When I first got to Melbourne, there were no juniors - no Harold Matts or S G Ball kids to draw on and we had to bring kids in from everywhere for that first year in the 20's in 2008," he says.

"There were no fathers or family there and for a lot of them, it was the first time they'd been away from home so we were their footy coach, their dad, their older brother. We were getting them to school, making sure they were going to school.

"It played a big part in my development as a coach because we had to set up a culture from zero and it was a culture where you needed to know the Storm way or you weren't going to survive down there."

Remarkably, Melbourne won the grandfinal in just their second year in the '20's comp in '09 on the same day the club won the NRL decider.

Bellamy had enormous faith in the hard-working O'Brien, promoting him into a newly created role of development coach where he upskilled individuals to prepare them for the top grade. O'Brien did a pretty fair job too. In 2011 and 12, Bellamy handed nine players their debuts.

Despite looking after defence for the most part up until that point, O'Brien's next promotion was as the NRL side's attacking coach.

"Probably the biggest thing Craig did for me at that point was to tell me 'that's yours, I want you to own it'." O'Brien said. "He just put some trust and faith in me and when someone does that, you are going to really dive in and give it everything and he didn't need to do that.

"Anyone would have loved that job and he didn't need to do that for me but he did. Then he and Frank [Ponissi] pushed me into a senior assistant role with more responsibility and that was the thing that rounded me out at the end.

"Craig moulded me, he is a great person, we get on really well, our wives are really close and when I told him about the offer I had to go to the Roosters who were the Storm's arch rivals, instead of being upset, he made me a life member. That's the mark of the man and the club."

As for his 12 months at the Roosters, O'Brien is every bit as grateful for the experience to work in another great system with a different philosophy of how to do things but just as highly successful with a coach in Robinson who he describes, along with Bellamy, as the ''absolute elite'' of coaches in any sport in Australia.

"So I've been fortunate enough to have done a pretty fair apprenticeship with Craig and Robbo - it's been awesome,"he said.

"If I was a builder, I reckon you would be content to let be build your house."

In recent times, O'Brien's name has been connected to just about every NRL job going. "But I wasn't in a rush,"he says. "I can honestly say this was the first one that I actually agreed to meet with. I was mindful of doing a thorough apprenticeship.

There is so much responsibility in being a head coach. You've got players that are handing you their life for 10 or 12 years and parents handing you their kids. I knew I had to be the right fit for the club just as much as the club had to be the right fit for me.

There's only 16 jobs like this in the world but probably two or three for me and this was right at the top. It fitted our lifestyle but the other thing was the region. I love how much they get behind the team. This one just felt right."

O'Brien says he is excited about the roster and the chance to develop and progress a host of talented young players coming through the ranks.

With the backing of Wests Group, he has beefed up his coaching staff to give players every chance of success provided they work hard enough.

He highly rates new hooker Jayden Brailey and has reversed the club's decision to off-load prop Herman Ese'ese, believing he has a lot to offer. He is chasing an outside back but can't wait to work with the likes of teenage stars Bradman Best and Starford To'a.

O'Brien says all the questions surrounding the mentality of the squad will be answered during pre-season training.

"You need to get them comfortable with being uncomfortable," he says. "The fade outs last season - that's something I need to fix. Why they existed, was it physical, was it mental? I guess if you are a guy that needs to be looked after all the time in terms of off-field, then you tend to be the guy that needs to be looked after during a game.

"You'll expect someone else to clean up after you. They'll have to make a tackle that was probably yours. That will come out in your character through your training and how we drive our values as a club."