Mr Greenberg, originally from New York, has lived in New Zealand since 1991.
He began volunteering at his local fire brigade aged 13, and used CPR to save a man a few days before his 14th birthday.
In 1990 he came to New Zealand on a one-year contract to work in computing and soon inquired with Wellington's Westpac Rescue Helicopter (provided by Life Flight) about work.
In 1991, they gave him a volunteer position and in 1995, Life Flight offered him a fulltime position.
For his dedication to Life Flight, Mr Greenberg has been nominated for a Pride of New Zealand Award, in the Lifetime Achievement category.
"He happily gets up in the middle of the night to help complete strangers and not just because it was his job but because he believes in it and loves it," his nominator said.
For Mr Greenberg, he couldn't think of anything else he would rather be doing.
"I ended up with this outrageously great job flying around the most beautiful country in the world and helping people, I mean, what more can you want out of life?" he said.
Mr Greenberg was responsible for the rescue of one survivor at the 2010 Anzac Day air force crash, which claimed the lives of three other men.
"It was a memorable crash, much because on any other day it could have been an air force helicopter hovering above us if we crashed.
"It was very personal, in a lot of ways," he said.
When Mr Greenberg is not up in the air, he is down on the ground volunteering for major rugby events.
For several years he has been a rugby sevens liaison, and during the World Cup was one of 20 volunteers selected.
The Pride of New Zealand Awards are proudly brought to you by The New Zealand Herald, The Hits and TSB Bank.
Nominations for the 2015 awards have now closed.
To see more stories of our wonderful nominees click here.
For more information on the awards go to the official website.