There's a fair argument to say the boy from Lower Hutt, who was just another a kid on his skateboard when John Walker's career was winding down in the early 1990s, has helped spark a middle distance renaissance in this country, as well as maintaining New Zealand's cherished history in the 1500m.
Three New Zealanders will compete in the event in Rio but between 1984 and 2004, only three New Zealanders qualified for the Olympics in the 1500m.
Tony Rogers finished a creditable ninth in Los Angeles but Peter O'Donoghue (1984) and Martin Johns (1996) didn't progress to the respective finals.
In 1988, 1992 and 2000, there weren't any 1500m representatives at all. Then along came Willis. He reached the semifinals in Athens, claimed silver in Beijing and was the oldest man in the London final, where he placed a disappointing ninth.
He's also won three Commonwealth Games medals, set countless national records and claimed a podium finish at the 2015 world indoor championships. In short, Willis put New Zealand runners back on the map.
"Nick has been a huge inspiration to us, being at the Games since 2004," says Julian Matthews. "He provided the motivation to get to this level."
Willis has inspired, but also instructed. He ran a training camp with other national runners in the last New Zealand summer and in recent months Hamish Carson and Matthews trained alongside Willis in the United States.
His conscious effort to leave a legacy - Willis regularly talks about giving back as much as he can - has paid off, with Matthews and Carson confirmed for the 1500m in Rio, giving New Zealand three representatives in the event for the first time. "I decided to come to the [US] based on what he and [coach] Ron Warhurst were doing together," says Matthews.
"His knowledge of the 1500m is amazing, and it's an honour to be part of his team. His pacemaking ability has allowed us to focus on one race, whereas a lot of guys seeking the qualifying time didn't have that luxury.
"Running can be a lonely sport, so this has been the best preparation I've had for a Games from an enjoyment standpoint," Willis says. "The solidarity has been unique. The Olympic concept can get routine, but seeing these guys so excited has been a joy and I've fed off their energy."
Matthews and Carson have also added a competitive edge to the sessions, as they have both set personal bests this year. "My wife gets worried because I'm not pulling away in workouts," laughs Willis. "She says, 'does that mean you're not in shape, Nick?' [But] the times are what I normally do, it's just they're right on my arse."
It puts Willis in a good place. He recorded the world's fifth fastest time last year and a personal best (3m 29.66s) and his form this year suggests he will be in medal contention at Rio.
At the very least, he will make history next month as the first New Zealand male track athlete to compete in four successive Olympics. "That kind of record means a lot to me but I've been lucky," he says. "I've been healthy every time the Games have come round and fortunate to go. It's the dream of a lot of people."
