It was his second most important achievement, after negotiating a free trade agreement with China.
While Mr Goff has moved his party to the left on other policy issues in the past three years in Opposition, Labour's outlook on trade remains orthodox and will do so as long as Mr Goff remains leader.
The TPP is one policy area in which Labour parts company with the Council of Trade Unions which has raised reservations about it.
The heat may come domestically next year when the tough parts of the deal are negotiated and if isolated parts of the text are leaked, as has been happening for some time from the US.
Negotiations are expected to gain momentum after American President Barack Obama threw his weight behind it at the Apec leaders' summit 10 days ago as the great hope for growth and jobs.
Prime Minister John Key missed out on the summit because of the election campaign. New Zealand was represented by Finance Minister and Deputy Prime Minister Bill English.
While trade is largely bipartisan, one area of difference between Labour and National is in their approach to NZ's presence in Afghanistan.
Labour, which sent the SAS there in in 2001, has changed its mind, saying the Government of Harmid Karzai is corrupt.
The SAS is due to come home by March but Mr Key has not ruled out a future deployment.
Labour would keep on only the 140-strong Provincial Reconstruction Team in Bamiyan while it developed a joint exit strategy with other coalition members.
The two main parties have differences over overseas development assistance, too.
National places more emphasis on economic development as a way to alleviate poverty, while Labour wants a stand-alone aid agency which emphasises poverty alleviation.
Labour spokeswoman Maryan Street concedes that other differences in the foreign affairs area, such as over multilateralism and human rights, may be a matter of emphasis.
While she believed National was committed to them, it did not promote them actively.
Mr McCully says National tends to approach other countries about their record in private rather than using megaphone diplomacy.
"We see being given the responsibility to conduct foreign policy in government as an opportunity to advance New Zealand's interests rather than an opportunity to live out our student protest fantasies," he said.
The improvement in relations with the US has been a hallmark of the National Government.
A partnership agreement was signed last year and the intelligence relationship was fully restored. Defence relations are improving as well.
Mr McCully believed that although Labour was keen to improve the US relationship, National did more to make it happen.
"Those differences of style do matter. Americans know that we are absolutely genuine about our desire to maximise the partnership and they've reciprocated."
He had also put more emphasis on New Zealand's leadership role in the Pacific and its responsibilities in the region, and into advancing the relationship with Asean, the Association of Southeast Asian Nations.
"But there aren't too many differences because foreign policy is about advancing the national interest."
That meant "as much consistency as possible in the way in which New Zealand presents itself".
Highlights
National
Promote stronger political and defence relations with United States.
Labour
Independent foreign policy. Withdraw SAS from Afghanistan but develop exit strategy for Provincial Reconstruction Team in Bamiyan.
Greens
Withdraw SAS from Afghanistan.
Act
Support free trade and investments; re-engagement with Fiji; and New Zealand's contribution to Afghanistan.
Maori Party
Immediate withdrawal of New Zealand troops from Afghanistan.
Mana
No policy supplied.
United Future
Self-determination of Tibet and Taiwan.
