Participation in the 12-year-old company's events is growing exponentially, particularly among women who now make up just under half the event fields.
From its Riverhead base on the outskirts of Auckland, Total Sport employs five full-time and five part-time staff, including Carter's wife, Nicola.
Event success hasn't always flowed through to the bottom line and, like other small businesses, Carter says, the past couple of years have been tough, with profits flat as overheads creep up.
Total Sport is now focusing on making the business more financially sustainable, improving the bottom line while still delivering value to its event participants. A planning session this year identified the need to add hard-nosed commercial nous.
Carter says it's about becoming lean without being mean or stripping out the goodness and value that keep participants coming back.
Securing the right person for the job - who is just in the process of signing on the dotted line - means Carter selling a stake in the company.
"It wasn't really about looking to sell shares in the business. It was about finding someone who could do a job and the point that we got to was he was keen to do a job but he's also got a business that invests in businesses."
It's the second time in a year Carter has brought in another shareholder to attract the right person to help grow the business.
"It has kind of happened that way that these two particular people that are now shareholders in the business have got the skills I wanted to bring to the business and both wanted to invest in the business. That was a real mental thing for me for a long time. I couldn't get my head around not owning 100 per cent of this business, but now I'd rather own 'x' amount of a successful business than 100 per cent of one that is shaky."
Keeping a sharp eye on finances and planning is a world away from Total Sport's early days, when Carter enjoyed a lifestyle based on his love of sport, but quietly fell further into debt.
He'd established the brand after taking voluntary redundancy from a job as events manager at Sport Auckland, the local arm of the sport trust network, in exchange for a $20,000 contract to run some of its events.
Carter assumed he'd pick up other events work, but a total lack of business planning and being a "no name" in the business made for a tough couple of years.
"At about that same point I got some advice from a business mentor, probably about four years too late."
It meant for the first time, devising a plan for the business and being clear that Total Sport was about taking people out to run, walk or mountain bike in spectacular locations.
Carter says Total Sport has been lucky to benefit from the rise of running and mountain biking - US magazine Runner's World calls it "the second running boom" - but also acts on feedback, particularly its annual survey of its 20,000-strong participant database.
A middle-of-the-pack runner and father of one, Carter says he is probably representative of those people: busy, 30- to 50-year-olds, well paid professionals who are competitive but not necessarily aiming for a podium finish.
Although he never competes in his own events, Carter says the Partners Life Dual, an off-road run and mountain biking event, on Motutapu Island in the Hauraki Gulf, is easily his favourite.
As well as raising money for tree-planting by the Motutapu Restoration Trust - $100,000 donated to date - Carter sees potential to attract international visitors.
"The Dual is something that I can see becoming just epic."
