"It's more important than ever before that journalism does what it should and holds the powerful to account, in particular in business and government, where they do have the ability to strongly influence New Zealand and people's livelihoods," she said.
The media played a key part during her career in reining in New Zealand's 'Wild West' share market, which "thrived on insider trading" and had few rules about takeovers.
"It had a big role in exposing the nefarious activities of quite powerful players, advocated for change and applauding change when it happened," she said.
Born in Blenheim, O'Sullivan undertook business studies at Victoria University of Wellington and started her career as a radio journalist in the parliamentary press gallery.
She edited the National Business Review in the mid-1990s and was Herald assistant editor from 2001-2005.
In a career of stories, one of her most memorable was the Air New Zealand collapse in 2001 where she led an award-winning Herald team: "That was sustained daily journalism at its best."
O'Sullivan was attracted to the profession because it offered the ability to make a difference.
"I tend to be a little bit activist in my approach and I've been at various times a strong campaigning journalist, particularly through the 80s and 90s. I do see journalism as having the ability to shine a light on things that need to be addressed."
As well, O'Sullivan has been instrumental in creating significant platforms to improve New Zealand's relationships and links with major trading partners.
She was a founding director of the New Zealand Apec CEO Summit board, which sought to leverage opportunities for local business from the 1999 Auckland forum.
O'Sullivan was also a founding director and a vice-president of the United States New Zealand Council, whose advisory board she now chairs.
She also sits on the New Zealand China Council advisory board.
With a trade war erupting between the US and China, O'Sullivan said it was essential New Zealand acted as a bridge between them to ensure the multilateral trading system endured.
"New Zealand's role to be an interlocutor is going to be quite important ... to ensure that debate is happening and relationships can remain as good as they can be and that includes business as well," O'Sullivan said.