He was only 12 on the morning after the 1985 Rainbow Warrior bombing.
"The class had fallen really silent and I heard the teacher say, 'Countries go to war over things like this'. I was really offended by the idea that a country that was theoretically our friend had bombed a ship that was doing something good in our own harbour."
But it was as a 16-year-old that Mr Shaw turned Green, while watching a debate where Green candidate Gary Reese talked about "the fate of the planet". Mr Shaw volunteered for his campaign and, two years later, stood on a Green ticket for Wellington City Council.
While studying international political economy at Victoria University, he reconnected with his father.
"I've rarely been so drunk," he says of the pub crawl that ensued.
In the late 1990s Mr Shaw, now London-based, was part of a team of bold PwC interns who pestered their bosses about sustainability. Today, PwC is one of the world's leading consultants on sustainability.
He later freelanced as a sustainability consultant, eating a can of baked beans a day during the less lucrative times, before taking on HSBC as a client in 2006.
While working towards a Masters in Sustainability and Leadership at Bath University from 2003 to 2005, he realised he wanted to be an MP.
"I'd seen the strengths of working in the corporate world, but there are some things in the world that will only ever change as a result of things that happen in the political domain."
After running the Green's campaign in London for the expat vote in 2008, he returned to Wellington in 2010, missing out in 2011 by one list place. He regrets having to watch the gay marriage bill from the sidelines.
"It was the biggest outpouring of civic engagement. If you lobbied your MP, you could change their mind. That's how it should be."
For every bill?
"My personal opinion -- that would be great. It would be chaos, but you would have to build a coalition for every bill."
He finds the sniping and adversarial side of politics a huge turn off.
"I hate tribalism and I loathe labels. That is as much a part of the problem as any particular policy."
How will he deal with it? "I have no idea."
Who?
• James Shaw, 41, business sustainability consultant
On climate change:
• "The West Antarctic ice sheet is melting. Tokelau is already non-viable. This is the thing that p..ses me off. It'll get worse in the future, but it is happening now, and we're pretending it's not a priority."
On political heroes:
• David Lange - "He led the country through the nuclear-free storm, and stood up to the world by forging independent foreign policy."
• Martin Luther King - "Led the civil rights movement at a really improbable period of time."
Interesting facts:
• Only got his learner's licence this year. "When I was 16 my mother offered me either driving lessons or a mountain bike. I took the mountain bike."
• Family blood is English, though he has a touch of Jamaican. "My first female ancestor in New Zealand was the granddaughter of a plantation slave (valued at - 80)."
