The American patient from McMurdo Station had a non-life threatening condition but required medical treatment that cannot be done in Antarctica.
Air Commodore Andy Scott said flights to the Antarctic at this time of the year were dangerous due to the extreme environment, which included temperatures of -33 degrees Celsius.
Because there was no daylight, the crew flew into the Phoenix Airfield wearing night vision goggles, he said.
The first time this technology was used by the RNZAF to fly into Antarctica was in July 2021 for another medical evacuation.
One of the pilots on Thursday's mission also flew on that mission.
With no airfields to divert to en route, the plane needed to be refuelled in Antarctica before making the journey home to Christchurch.
"The pilots have a point of no safe return when they make the decision to continue or turn around, known as a 'boomerang'," Air Commodore Scott said.
The Hercules was "hot fuelled" on the ice, where the engines were kept running to protect them in the extreme cold.
"The weather had deteriorated again on arrival and so they have threaded the needle to get in when they did," he said.
It took more than seven hours to return to Christchurch.
The US ambassador to New Zealand, Tom Udall, thanked the RNZAF, calling the rescue a "world-class medical evacuation".
"Piloting in the dark, in the most challenging of weather conditions, in the middle of winter, is simply extraordinary flying.
"Our longstanding, bilateral cooperation in Antarctica, and to and from the ice, is always deeply valued - but especially meaningful today. Thank you for your service."
