Rehberger works in the wider sphere of design and architecture, and his art is difficult to categorize. He has created an idyllic Japanese garden in the middle of Manhattan; Pop-inspired wallpaper consisting of photographs of his organs; a series of Modernist-looking treehouses in a park in northern Germany; and an enormous tanker based on a crude boat that the father of a friend built to escape from Vietnam.

For his art-car series, a project that he began in 1999, Rehberger sent simple sketches, composed essentially from memory, of a Porsche 911 and a McLaren F1 to a manufacturer in Thailand. There were no measurements or schematics included. The only parameters were that the cars had to be drivable and built to human scale.

Rehberger also spent some time in Cameroon, where he provided native crafts workers with his crude drawings of well-known modernist chairs and asked them to recreate the designs. The results were filled with cultural misreadings: Alvar Aalto's classic three-legged stool, for instance, was given an extra leg for stability.

On the East side of the Madison Square Park in New York, Rehberger in 2001 created Tsutsumu, an elegant Japanese garden made up of a large bonsai tree, a bench and a rock. Early in the morning, even on sweltering August days, the Public Art Fund sprayed the garden with four inches of man-made snow.

In December 2011, Rehberger unveiled his public sculpture Obstinate Lighthouse, commissioned by the City of Miami Beach. In 2012, he was commissioned to design a 700 square feet (65 square metres) project space in the Leeum, Samsung Museum of Art in Seoul, Korea.