The surgeon has carried out 30,000 operations in conflict zones such as Sudan, Cambodia and Afghanistan, mostly on desperate people caught in the crossfire of war. No wonder he has some forthright views on war, healthcare – and why President Obama oversees a killing machine

Three years ago, the photographer Giles Duley walked into the Salam centre hospital in Sudan and was taken aback by what he saw. It was unlike any hospital he'd seen anywhere, let alone a country as desperate and chaotic as Sudan.

It performed world-class open-heart surgery free of charge, it was calm, ordered and spotlessly clean. "I mean absolutely spotless," says Duley. "I've never seen anything like it." At its centre was a beautiful garden. And there, in a corridor, he found the only unruly aspect of the entire operation: the man who created it all, a bearded, straggle-haired Italian called Gino Strada, leaning against a wall, chain-smoking.

In the studio in east London where Duley was photographing him for the Observer last week, Strada was still straggle-haired, still chain-smoking: "Though I can stay 10 hours at the table in the operating room and I don't even think about a cigarette," he says stepping outside to have a quick one between doing the interview and having his portrait taken. "I don't even think about it until it's over."

The operating room is where Strada lives. He's a surgeon, a heart-lung transplant surgeon by training, who should be living comfortably in some well-to-do Italian suburb, but who instead has devoted the past two-and-a-bit decades of his life to living uncomfortably in some of the worst places on earth.

Aged 65, when other men's thoughts might turn to retirement, Strada spends months-long stints in Afghanistan, Iraq, Sudan or any other of the 47 healthcare centres worldwide set up and run by Emergency, the NGO he founded. Although both Strada and Emergency are practically unknown in the UK, he has quietly got on with doing the world's dirty work: Emergency provides free high-quality medical care for the victims of war, 90% of whom are civilians, and the majority of whom are poor and have nowhere else to go.

"We think everyone has the right to be cured," he says with the air of a man who's been saying the same thing for decades. But then he has been doing exactly that. Which in part explains the world-weariness that accompanies him like a particularly faithful dog. ("He may appear tired and cynical on the surface," says Duley, "but underneath he never relents.") Strada has seen the very worst the world has to offer.

Even the most committed doctors rarely manage more than a few months in a war zone. Strada has done years and years. Emergency, in its 18 years of existence, has treated 5 million people under some of the most dangerous conditions in the world. He personally has operated on 30,000 people; an almost unimaginable number, I say.

"Yes, but I always find it very, very interesting. When I wake up in the morning, I'm happy to go to the hospital. When I worked in Milan and I woke up in Italy, I wasn't that excited; it was more like a routine."

Emergency is doing extraordinary work, and yet that is not the most extraordinary thing about it – not the thing that struck Duley so forcefully when he walked into the hospital in Khartoum. The Salam centre for cardiac surgery is not some bush hospital patching people together with sticking plaster and a couple of aspirin: it offers world-class free cardiac treatment to patients from across Africa. (Many of its patients are young: rheumatic fever, which is endemic in Sudan and neighbouring countries, destroys the heart valves and disproportionately affects children and teenagers.) It's the only hospital of its type on the entire continent and Strada's view, which challenges most people's ideas about how "aid" works, is quietly revolutionary. He believes that Emergency's hospitals need to equal if not better those in the west.

But nobody believes that, I say. No other organisation is saying this.

"If you think of medicine as a human right, then you cannot have some hospitals that offer sophisticated, very effective, hi-tech medicine," he says, "and then go to Africa and think, 'OK, here's a couple of vaccinations and a few shots'. Do we think that we human beings, we are all equal in rights and dignity, or not? We say, 'Yes, we are.'"

At Emergency, he says, "we want to establish good hospitals, but how good should a hospital be to be good?" After a lot of debate, they decided the measure should be: "if it's good enough that you would be happy to have one of your family members treated in it".

Emergency's hospital in Sudan is so clean that infection rates aren't just lower than in hospitals in the UK and the US, they're "lower by a power of 10". And the cardiac centre is just the first in what he hopes will be a network of these specialist hospitals, all centres of excellence, that will stretch across Africa, the next being a paediatric facility in Uganda, designed by his good friend, the Italian architect Renzo Piano.

There's an almost Fitzcarraldo quality to Strada – the Werner Herzog film about the man who pulled a steamship over a hill in order to build an opera house in the Amazon jungle. People thought Strada was nuts "and worse" when he decided to build a cutting-edge, world-class cardiac hospital in the Sudanese desert. "They wrote all kinds of things about it and me in Italy." But he did it anyway. A children's hospital on the shores of Lake Victoria designed by the man who co-created the Pompidou centre is relatively straightforward in comparison.

But then Strada negotiated with the Taliban at a time when Nato said negotiating with the Taliban was impossible, in order to operate a hospital behind their frontlines. He considers himself a surgeon above all else and, as a surgeon, he just likes fixing things.

"Emergency is just not like any other NGO," says Duley. "I've worked with so many of them, but it's just profoundly different in the way it treats people with such dignity and such respect. The hospitals are such oases of calm, they're incredible."

It's impossible not to make Duley a part of this story, because he has championed Strada and Emergency's work. He's passionate about getting their story heard. During his visit to the Salam centre in Sudan, Strada urged him to visit Afghanistan, which Duley did. While he was there, as we've covered previously in the Observer, he was blown up and lost both legs and one of his arms. (Strada feels terrible about this "though it's incredible to see Giles now, how it's just made him even more determined".)

"I knew that the first story I did afterwards would get a lot of attention," he said. "And, for that reason, I knew I wanted it to be about Emergency." It's only because of Duley's urging that Strada has stepped out of the shadows, appearing at two events in London last week.

And there's no doubt that Strada's work deserves to be better known. In Afghanistan alone, it operates four hospitals and 34 clinics. It has opened three during the past month. Strada says that the Red Cross has pulled 95% of its personnel out of Afghanistan "now the war is over" and Nato forces have built not one civilian hospital. "And the war is not over! The fighting is getting closer and closer to Kabul." The casualty figures were up last month, he says, by 40%. We went to war in Afghanistan. Our government did so on behalf of us the people. And it's been left to a small Italian NGO to mop up our dirty work.

"It's absolutely criminal… I mean, you know Nato forces, they have their own back-up system. Their own medical facilities. And for the population there is nothing left. And even more than that, the Afghan government has to record the cost of the services international aid organisations provide, so it's going to pay in the end. Very few can afford treatment, and for all the others there's nothing. Therefore, if you're injured or you're sick, you just die, period."

Opening and running one of his hospitals for three years costs €3m (£2.5m – "or the cost of three western soldiers for a year"). Drones – the victims of which they're seeing in increasing numbers, at least 40% of them children – are just another obscenity. "Particularly if you think that thousands of miles away someone is putting down a killing list. The Nobel peace prize is signing a killing list every week."

What do you mean? "I mean, President Obama. He's personally signing a killing list. They have squads of assassins, professional assassins, who kill people. Is this the idea of justice of the new millennium, that someone gets killed because someone else decided this one deserves to be killed without a trial, without pause, without nothing? Just crazy, crazy. It's another human way to wage war. It's not a human one, but this one is particularly nasty and particularly cruel."

But then Strada believes that war should be abolished. Abolished?

"It has to disappear from human history," he says. "Same as slavery had to disappear from the human history… and today the concept of slavery is disturbing." War should disturb us equally, he says. It makes absolutely no sense. "It's very peculiar to the human race and it's crazy because what you are destroying is humanity… When you operate on children and teenagers, you ask yourself what the hell do they have to do with war? I mean, these people, they don't even know why a war is fought around them, and they don't even know who's fighting whom."

He reserves his harshest judgment for "humanitarian wars". "Whoever speaks about humanitarian war should be eligible for a long stay in a psychiatric institution. It's complete nonsense. No matter what people say or think, the end result is that 90% of victims are civilians."

There are few people who can talk with the moral authority of Strada. He has earned the right to be listened to. Few people have seen the things that he has. Far fewer have done anything about it. He challenges you to think differently about things you thought you knew about (the inevitability of war, the inequality of suffering) and simply refuses to accept the status quo.

Duley is right. The world-weariness is a front. And there are signs that the world is starting to notice a little. A documentary short about the Salam centre, Open Heart, was nominated for an Oscar this year and Strada found himself flying from Afghanistan to the Academy Awards. But, given the scale and scope of his work, it seems ludicrous that he's not better known.

He travels continuously. He rents a house in Venice but is there for only a few weeks of the year, for only a few days at a time. He's had open-heart surgery himself: a quadruple bypass after a heart attack he suffered while under fire from Saddam's forces in Iraqi Kurdistan a number of years ago. And in 2009, his wife, Teresa, with whom he co-founded Emergency, died.

Has it been difficult continuing alone? "It has, although it might sound strange, but it gave a bit more strength because we didn't want to waste everything that Teresa had given. She developed Emergency in Italy, and we now have 4,000 volunteers there, and these people decided to support Emergency's work because of Teresa."

His daughter, Cecilia, now continues her work, and Strada is back on the road. Don't you ever think sometimes you should be at home in Venice tending your roses? It's a nice idea, he says, but "I'm a surgical animal. I like to be in the operating room." The roses will wait.

To learn more about Emergency and how to volunteer or donate, click here