His new club had just won their fourth successive Aviva Premiership match and were perched at the top of the table.
But, just two and a half months later, Darbon was helping to make one of the biggest, and most difficult decisions in the club’s recent history.
Saints were forced to dispense with the services of long-serving director of rugby Jim Mallinder after results took a nosedive.
The black, green and gold had tumbled from the league’s summit and were on one of the worst sequences of form the Gardens had witnessed.
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Mallinder saw his 10-year tenure, which encompassed several trophy wins, including the club’s first Premiership title, reach its conclusion.
And a series of other changes have followed as Saints seek to arrest a startling decline that began after they finished top of the Premiership for the first time in 2015.
Chris Boyd will arrive as director of rugby this summer, taking over from Australian Alan Gaffney, who has been the technical coaching consultant since the turn of the year.
And several key figures will be going in the opposite direction to Boyd, with the likes of Dorian West and Stephen Myler heading for the Gardens exit door at the conclusion of the campaign.
It is easily the biggest summer of change in modern times, and Darbon has been the man to oversee it.
So just how does he reflect on his first season at Saints, having moved to the club last July for the next step of a career that has included helping to deliver the London 2012 Olympics?
“First and foremost, it’s brilliant - I absolutely love it,” Darbon said.
“It’s a great club, the people are fantastic, we’ve got a great facility, incredibly loyal supporters, so if you want a job in sport, what a great place to be!
“I am loving it.
“I’ve been here eight or nine months but it feels like a lot longer than that because we’ve been through so much change.
“You can look at it in a couple of ways: be focused on the challenge that comes with that change or be focused on the opportunity it brings for the future, and we’re all trying to get ourselves into the latter category.
“We’re all focused on making the right choices now to set us up for sustainable success in the future.
“It’s been full-on. Not having a director of rugby, not having a commercial director for significant chunks of my tenure has been difficult from a personal perspective,but I’m pleased with the choices we’ve made because I think they will stand us in good stead.”
How difficult was it for Darbon to bring an end to Mallinder’s time at Saints?
“It was really difficult,” he said.
“Jim oversaw a fantastic period of success for this club and no one should forget that. It was one of the most remarkable periods of success in the club’s history.
“He had been here a long time, was very popular among staff and supporters.
“From a personal perspective, Jim had been amazing with me in helping me get up to speed with life at the club and understand how they approached things in the rugby department.
“So it was a really difficult decision, but at the same time, we’re in a performance-led environment and in the past two or three years, we haven’t been getting the results we think this club warrants.
“We felt it was right to make a change. It wasn’t easy, but we think it was the right decision.”
Darbon took over the role of CEO from Allan Robson, who retired after being at the Gardens for almost two decades.
And it is clear that the new CEO has brought plenty of fresh ideas to the position, meaning long-standing loyalties are no more, even though he has been extremely keen to embrace the club’s illustrious history.
“The club needed some fresh eyes and that may be a reason why there has been some change,” said Darbon, who counts Tough Mudder among his former employers.
“It is really important to understand the history and heritage of Northampton Saints because so much of what we do and what we’re about is rooted in that history.
“I’ve been desperately trying to get up to speed with that history, whether that’s through getting to know people who are part of that history, or brushing up on what’s happened in years gone by.
“We will never forget the history and heritage but having a fresh perspective on the commercial side of the business and the rugby side has been beneficial.”
Darbon and Saints are now hoping that Boyd, who will leave his role as head coach of Super Rugby side the Hurricanes this summer, can bring the good times back to the Gardens.
The Kiwi boss recently travelled to Northampton for a week to assess the club and stamp his mark on matters, including recruitment and retention.
Darbon said: “Chris has been involved in those decisions and one of the things I’ve been really pleased with is how involved and engaged Chris has been since we made the appointment, even though he’s running a Super Rugby franchise and they’re in their season right now.
“The majority of our decisions on the rugby side have Chris at the top of the tree in terms of that decision making, whether that’s players, coaches or pre-season and all the other stuff we’re working through.
“A lot of those decisions have his mark on them somewhere.
“We do talk about the financial side. We’re not at the stage yet of giving Chris a budget, we’re managing that closely and that’s part of my job and others at the club.
“Chris has got a good understanding of the make-up of our squad, the areas we need to look to strengthen and areas where we have some tough choices to make on players who are reaching the end of their contract.”