Mr McCully praised medical staff saying that while his encounter with the health system was longer than he would have liked "the bottom line is I had a good outcome".
"I was a lot luckier than some other people are so I am feeling very grateful about them."
Mr McCully has had a punishing travel schedule in the past few years, particularly campaigning successfully for a seat on the Security Council, and he will ease back into it.
"I'm just to make sure that I don't set myself international travel schedules that are guaranteed to wipe me out.
"Apart from needing a bit of time to build stamina and strength, I am not anticipating any long-term impact."
Prime Minister John Key was acting Foreign Minister in his absence.
Mr McCully said one of the first things he will be doing this year is to take a paper to Cabinet to lift the UN sanctions against Iran, following similar moves overseas in line with the agreement to limit Iran's nuclear capability. The sanctions were imposed in 2011, when Iran was refusing to co-operate over its nuclear programme.
Since 2011 it has been unlawful for any New Zealand company doing business in Iran without registering with the Ministry of Foreign Affairs.
Mr McCully admits the sanctions have not had much impact - but those of other countries which has affected potentially large trade deals.
"The real impact on New Zealand business has not been from the UN sanctions but really the US banking sanctions which have made some of the big trade deals basically unbankable."
Another priority would be what New Zealand does in its second and last year on the Security Council, including the situation in Syria, Iraq and the Middle East peace process. April could be a busy month with China chairing the council.
Mr McCully said he also wanted to catch up with counterparts in Australia and in Fiji, two events he had to postpone last year. The Pacific was high on his agenda, too, with the development programme in the early stages a new three-year funding cycle.
He refused to comment on the Auditor-General's report into the Saudi sheep deal, even to say whether he had been interviewed.
Mr McCully has been MP for East Coast Bays since 1987. It is considered unlikely that he will stand again as an electorate MP in 2017, but he could stand on the list or retire altogether. He said that later in the year he would consider his future and discuss it with the Prime Minister.
Minister of a lot
• Has been an MP since 1987.
• A lawyer, he served in cabinet in the Bolger-Shipley administrations, and in the Key Government
• He has attracted his share of controversy and survived some political scrapes, most recently the row over the Saudi sheep deal
• In the 2015 New Year honours he was made a Companion of the New Zealand Order of Merit for service to foreign policy.