She was the first of her family to stay at school past the age of 15, at a time when women were encouraged to become either nurses, teachers or secretaries. After school, she worked as a secretary in a law firm.
One day, she heard a presentation at Massey University and realised the secretarial life wasn't for her. She quit that day and signed up for computer science, accounting and finance, graduating effectively with a triple major in just three years.
She got a job at Price Waterhouse in Wellington and was put on a fast-track programme. At that time, New Zealand companies were restructuring and she got to work with the American companies coming down to the region.
"I was in the James Cook Hotel and one of the Americans - Greg Kidd - advised me to do a masters degree in the US. I thought he was crazy, but then thought: why the hell not?"
Throwing caution to the wind, she headed for the States and ended up being accepted into six of the top business schools, choosing the renowned Wharton Business School.
From that point on, she says her life can be divided into two phases. The first is building Dispatch Management Services (DMS) into a $230 million same-day delivery firm operating in 80 cities. She also became the first New Zealand woman to list a company publicly on the Nasdaq exchange.
The second starts at the point when she realised building one globally and financially successful company wasn't enough - "just in case it was a fluke" - so she started more, including a concierge business called LesConcierges, which became the world's leading corporate loyalty concierge programme.
"In this phase, I had two children (son Tristram now 15, and daughter Isabelle, 12), two companies and two social causes," says Jenkinson, who admits a typical day doesn't exist in her world.
"I'm on the New Zealand Olympic Council, so spent two weeks in Rio supporting the team and brand New Zealand. I went from that to a one-day orientation session learning about Australian insurance and superannuation after joining a board in Australia. Before that, I was in Wellington for the Bledisloe Cup with my godson from London and my Kiwi mates," says Jenkinson.
"I talked to Unicef NZ to give them a perspective on how to disrupt the NGO space and met various people in New Zealand about environmental and business ideas to do with creating a circular economy. I was also sailing on Sydney Harbour and spent the day at the Sydney office, where I have 100 people and I was supporting the team on client strategies."
I have a fundamental view of creating businesses that are win-win-win: for the business owners, for the employees, and for the environment
The day after we spoke, she was off to a conference then to San Francisco to meet her American friends at the Sausalito Arts Festival, before heading to Silicon Valley with Air New Zealand to learn about disruptive ideas for airlines, then back in New Zealand and Australia before heading over to Paris.
With all that going on, she still found time the day we spoke to go to Pilates, have a walk in the park and head to a Wharton Business School-hosted global forum.
It's not all business for Jenkinson, however, who met her husband Nick while skiing in Austria and - like many events in Jenkinson's life - this too had a sense of serendipity.
"I was living in New York and I had a bet with my flatmates about who could get into the most trouble over the Christmas vacation," explains Jenkinson.
"Without that bet, none of it may have happened." The man she set her sights on to "get into trouble with" was Nick, her future husband. After a few days together skiing, he promised to come to London, where she was heading next, and ended up cutting his holiday short to keep the promise. However, he lost her details and only remembered the suburb she was staying in.
"I was out with some Kiwi friends and told them about this man I had met. One was driving home and saw a guy with a huge ski bag and asked if he was Nick, and it was. He asked how he could find me," explains Jenkinson, who has been married to him for 24 years.
She counts her blessings but doesn't think luck comes into the equation when it comes to her business success.
"I simply figured out how to build companies," says Jenkinson. "I have a fundamental view of creating businesses that are win-win-win: for the business owners, for the employees and for the environment, and my goal is to build 10 circular businesses with global impact from New Zealand."
However, despite her loving New Zealand, she says The Tall Poppy Syndrome is one of the reasons she has based herself in America for 25 years.
"There's a fundamental belief in America that the pie will be bigger by working together, that other people's success is your success - it's a very inspiring and supportive environment to work in," says Jenkinson.
"It's far better than thinking 'We have one pie, let's fight over who can get it'." Her advice to budding businesspeople is to view business as a process.
"If you decide to become a nurse, you learn how to do it, then do it 5000 times to master it," says Jenkinson.
"Business is the same, just like you've mastered nursing, business is a different skillset and it's just something to master. Luck has nothing to do with it."
Not only is she a serial entrepreneur, but also a social entrepreneur, volunteering fundraising efforts for red cross in the US and co-founding WOW Investments, which was acknowledged as the most successful SME investment model in Africa.
One of her favourite quotes is by Gandhi: "Be the change you want," and she believes everyone can be an entrepreneur, but it's a case of learning that state of being, by putting yourself right in the middle of it.
Although she's extremely pleased with how her life has turned out, it wasn't a smooth ride. But, instead of getting down about setbacks, Jenkinson learned to see them instead as "periods of reinventions".
"It's all signals of where to focus your energy and I see it as part of the process, rather than good or bad things happening in life. If things don't work, it means you're in the wrong direction. You've got to figure out how to adapt, rather than emotionally connecting with events as being good or bad, because good can be bad and bad can be good in the end.
"Also, I never forget that I'm a Kiwi, so if everything goes wrong I can get a Kombi van, home school my kids in Europe and go explore," says Jenkinson, but there's no threat of that yet and she's not slowing down. Phase three of Jenkinson's story is just beginning.
