He wore a uniform of studiously mismatched socks, quirky hats, and patched and handmade trousers and shirts—assuming it wasn’t an occasion when he simply eschewed clothing altogether. He railed against straight lines—calling them “the work of the devil”—embraced exuberant color and rebuffed critics to champion art’s potential for mass appeal. His moniker was a carefully considered nom de plume. By the time of his death in 2000, Friedensreich Hundertwasser was known as an eccentric and brilliant modernist artist, architect, environmentalist and philosopher; a man as lambasted by the critics as he was embraced by the public.

It was a reputation he had spent a lifetime meticulously crafting.

After dropping out of the Academy of Fine Arts, Vienna, at the age of 20 after only three months, the Austrian artist—born Friedrich Stowasser in 1928—would do little to endear himself to the art establishment. While his peers were expressing the darkness of the times with monochromatic palettes, Hundertwasser mixed his own oils to achieve vibrant colors, preferring to paint on rainy days, when hues shine their brightest. His canvases of free, childlike forms, infused with light, were more reminiscent of Gustav Klimt and Marc Chagall than of his contemporaries and earned him few props, though he was successful with the public from the start.

“If he was known by critics, he was reviled,” says the Smithsonian’s Harry Rand, who spent five years interviewing Hundertwasser for an eponymous book about the artist. “Rather than seeing beauty as a byproduct of art, he recognized it as a priority, which is a dangerous political idea to start with since that gets close to kitsch,” Rand explains. “After all, what is kitsch but telling an audience what it already knows?”

Hundertwasser’s paintings might have had no obvious agenda other than bringing joy to the viewer, but the artist lived his life with gravitas and a sense of mission. He espoused the importance of saving the environment as early as the 1970s, creating and championing a flushless toilet, and published a manifesto about obligatory tree-planting in urban environments. He worked without a fee to design Hundertwasser Haus, a low-income residential building in Vienna, and he delivered frequent and ferocious lectures to audiences, occasionally in the nude. And while he was successful enough to own homes across the globe, from Venice to Paris to New Zealand, he kept only two sets of clothing.

“He said that he set out to accomplish two things,” remembers friend and Montreal art dealer Robert Landau, who holds the largest private collection of the artist’s work. “One was to live on no money, which he succeeded in because he lived off of everyone else’s, and the other was to make the world a better place, which he also did.”

From the beginning of his career, Hundertwasser was savvy about selling his art so that the work would be profitable but still retain its integrity and accessibility. Jack Rutberg, a Los Angeles-based dealer and friend of the artist, says, “He was interested in a broad impact and democratization of an image, so he started doing prints, but while he’d make and sign 10,000 of them, he would try to bring exclusivity to (each one). He’d make a color shift or add a unique variant.”