Liddell has been in Auckland this week announcing the latest investment of Next Foundation, the environmental and education fund he chairs.
It plans to invest $100 million into various projects over the next 10 years.
The latest investment, Project Taranaki Mounga, is aiming to transform the ecology of Egmont National Park, initially through pest eradication.
The world of philanthropy is a big change from the senior roles Liddell held at Microsoft and GM, which followed other top positions including a stint as co-CEO of investment bank Credit Suisse First Boston and chief executive of New Zealand's Carter Holt Harvey.
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He jumped ship from Microsoft to join the Detroit-based automaker in January 2010, when the firm was still reeling from the upheaval of the global financial crisis.
Only months earlier, the US Government had bailed out GM to the tune of US$50 billion.
Liddell helped steer company through a US$23 billion initial public offering in November 2010, before leaving GM a few months later.
Yesterday, he said the chances of him taking on another big overseas executive role were slim.
"I'm moving into a new phase of my career, but you never say never," Liddell said.
"What I've found in my life is opportunities come around when you least expect them."
He said a big New Zealand corporate role was also an unlikely prospect.
"If I was to spend more time down here in New Zealand, which I hope to, I would probably spend the great bulk of that in the philanthropic area."
Liddell has been the chairman of New Zealand accounting software provider Xero since February 2014, and said he was enjoying the role.
"I'm still very positive about Xero's long-term prospects," he said.
"I really love the company. I love Rod Drury, who's the CEO. I think he's a real tech visionary and I love the grand ambitions that he has to create a global company from a New Zealand base."