The 31-year-old right-armer made his debut in the second test against Zimbabwe in Bulawayo last night.
It had been a long wait for the towering paceman.
He toured England twice and was in the subcontinent when New Zealand beat India 3-0 last year.
But he was overlooked for selection, and he had started to wonder if he would ever get the red ball in his hands at international level.
It was a special moment for him when Black Caps coach Rob Walter gave him the nod.
"Yeah, actually a little bit emotional," he said.
"Rob sort of tapped me on the shoulder at training.
"It’s been a wee while coming. I’m not a spring chicken any more.
"I guess at certain points in your career, you wonder if it’s ever going to happen.
"But to finally get that nod, it’s a pretty special feeling."
Duffy made his debut for Otago as a fresh-faced 17-year-old and picked up three wickets in a T20 game.
His domestic career was not always smooth sailing. As Otago coach, Walter actually dropped Duffy for a time.
Duffy had picked up some bad habits while trying to add pace, and Walter felt it would be helpful if he returned to the nets to work on his action.
When he returned, he was a more consistent performer and was able to swing the ball again.
But Tim Southee had a mortgage on the test spot for more than a decade, so Duffy had to wait patiently.
He made the most of the opportunities he got at international level in T20s and ODIs.
But he desired a test spot — and is now the first Southlander to play test cricket in 47 years.
The late Robert "Jumbo" Anderson was the last Southlander to play test cricket for New Zealand. He played the last of his nine tests in 1978.
When looking back over his career, Duffy said many people had helped him along the way.
Former Otago cricket staff member Mark Bracewell was an early influence, as was former Otago coach Vaughn Johnson.
[When] I reflect on the things I’ve done to get here in terms of my action change with Rob back in the day and little tweaks here from a Jurgo [Shane Jurgensen] or a Jake Oram.
"I guess, as a player, it’s for you to sort of manoeuvre in and around all those coaches and find out what works best for you.
"But, you know, the most special one, I guess, is the family.
"[They] never doubted the journey once. When it looked like it wasn’t going to happen, they were still there the whole time supporting."
Duffy did not have long to wait to get into action last night; the hosts won the toss and batted and he opened the bowling with Matt Henry. Six tidy initial overs returned none for 12.
Duffy was joined on New Zealand test debut by fellow seamers Matt Fisher and Zak Foulkes.
Henry made the early breakthrough in the third over, having Brian Bennett caught by Will Young at second slip for a duck — although celebration turned to frustration when Young then dropped an arguably easier chance from new batsman Nick Welch next ball.
Henry got his man nonetheless though, trapping Welch lbw in his eighth over for 11.
Foulkes then claimed a first test wicket, having Zimbabwe’s premier batter Sean Williams caught in the slips — by Young, who dived to his right to snatch redemption — for 11.
In the last over before lunch, Foulkes combined again with the busy Young to nick off captain Craig Ervine for 7, sending Zimbabwe to the sheds slightly early at 67 for four.
Brendan Taylor — back in national colours for the first time after serving a three and a-half year ban on corruption charges — was still at the crease on 33.
