Ban, 56, is the seventh architect from Japan to receive the honor, which will be officially awarded in June. For two decades, he has rushed to the site of disasters—for example, the 1995 earthquake in Kobe, Japan, or the 1994 conflict in Rwanda—to construct temporary relief shelters. He has often used cardboard paper tubes as building materials, since they are easily found, easily transported and can be water-proofed or fire-proofed.
Ban's relief work has not been limited to creating living shelters. In the wake of the 2009 earthquake in L'Aquila, Italy, for example, he created a temporary auditorium so the city's musicians could continue to play. And after the 2011 earthquake and tsunami in Japan, he created partitions for existing emergency shelters so families could have some privacy.
Outside his humanitarian work, Ban's noted projects have included the Centre Pompidou-Metz, a modern art museum in Metz, France, that features a remarkable curved roof made of timber—and inspired by a Chinese hat.
In its citation, the Pritzker jury noted Ban's unique approach to materials.
"He is able to see in standard components and common materials, such as paper tubes, packing materials or shipping containers," the jury wrote, "opportunities to use them in new ways.
It noted his "Naked House" in Saitama, Japan, in which the architect used clear corrugated plastic on the external walls and white acrylic stretched across a timber frame to create a home that questions "the traditional notion of rooms and consequently domestic life."
Ban's "Curtain Wall House" in Tokyo uses two-story high white curtains to open or close the home to the outside. Similarly, his "Metal Shutter Houses" in New York's Chelsea neighborhood feature a unique metal shutter system to open up apartments to the city air.
But it is Ban's humanitarian work that the Pritzker jury emphasized in announcing the prize, which will be formally awarded June 13 at the Rijksmuseum in Amsterdam. "Where others may see insurmountable challenges, Ban sees a call to action," the citation said.
Speaking in an interview this week in one of the distinctive "Metal Shutter House" apartments, Ban, who has offices in Tokyo, Paris and New York, explained that despite his extensive work for private clients, his humanitarian efforts are of utmost importance to him.
"This is my life's work," he said.
Architects, Ban noted, are lucky because they always work for people who are happy—as people generally are when they're building a house.
"After I became an architect I was very disappointed in our profession," he said, "because we are mostly always working for privileged people, with power and money. So I thought that architects needed to have more of a social role. I thought we could use our experience and our knowledge for people who need help in a natural or man-made disaster. Even something like temporary housing, we can make more comfortable and more beautiful."
In times of disaster, building materials can be difficult and expensive to procure. That's why, Ban said, his favorite building material is something most people throw out: cardboard tubes.
"Even in Kigali, Rwanda, when I was building shelters, I found them," he said. "I'm not inventing anything new, I'm just using existing material differently."
In 2011, when Japan was rocked by an earthquake and tsunami, Ban first created partitions to help families keep their privacy in shelters like gymnasiums. Then he built, on the grounds of a baseball stadium, a three-story temporary shelter to house 19 families.
After the Kobe earthquake of 1995, he built a "Paper Church" which remained there for 10 years, he said, because of affection for it. Ultimately it was dismantled to make way for a permanent structure and rebuilt in Taiwan as a community center.
"Even a building that is made of paper can permanent, as long as people love it," he said. "And even a concrete building can be temporary, as we see in earthquakes."
Ban grew up in Japan and traveled to the United States at age 17, hoping to study architecture at Cooper Union in New York. But he learned upon arrival that the school didn't take foreign students, except as transfers. He discovered the Southern California Institute of Architecture, where he studied for several years, and eventually transferred to Cooper Union.
In 1985, he started his own practice in Tokyo. One of his earliest projects: A boutique for his mother, a fashion designer.
Now based in three cities, Ban said he felt nonetheless a little underqualified for the Pritzker award.
"It's too early," he said. "I haven't achieved enough, so I am taking this as encouragement for my future work," he said. He also said he wanted to be careful not to let the prize cause him to expand his offices and overstretch himself.
Ban mused that he gets similar satisfaction seeing people enjoy his most expensive designs or his simplest structures of paper.
"Sometimes people are so happy in my temporary shelters that they don't want to move out," he said. "And the same with my work for private clients. The satisfaction is the same—I just love to make nice spaces for people to enjoy."
Sponsored by the Hyatt Foundation, the annual Pritzker Architecture Prize was established in 1979 by the late entrepreneur Jay A. Pritzker and his wife, Cindy, to honor "a living architect whose built work demonstrates a combination of those qualities of talent, vision and commitment, which has produced consistent and significant contributions to humanity and the built environment through the art of architecture."