Encouraged by Jean Badovici, Eileen ventured into architecture. Her first house project in 1923 was inspired by Adolf Loos's The Little House. Her masterpiece is the E1027 House in Roquebrune-Cap-Martin (1926-1927), built on stilts and featuring highly functional interiors, where she experimented with new materials and techniques. Her paradoxical humor was reflected in her furniture designs, such as the Transat chair, the Satellite mirror, the Bibendum armchair, and the one-armrest seat.
From 1926 to 1929, she designed tubular furniture prototypes sold in her gallery, described as "camping style." These pieces followed a systematic logic: they folded, rotated, interlocked, and retracted. In 1929, she became a founding member of the Union des Artistes Modernes, separated from Jean Badovici, and closed her gallery and lacquer workshop in 1930.
Returning to the south of France, she built the house Tempe a Pailla (1934) near Castellar on ancient foundations. Each room was conceived as a self-contained space, integrating both interior and exterior environments. During World War II, Eileen continued to draw, paint, and reflect. In 1954, she built her final house near Saint-Tropez, characterized by great simplicity. She continued working on projects until her death on October 31, 1976.Around 1907, textiles became another passion for Eileen Gray. With her childhood friend Evelyn Wyld, she traveled to Morocco to learn weaving techniques. They established a workshop at 17 Rue Visconti, managed by Evelyn. Eileen’s textile designs were boldly abstract.
Although she contributed to the Art Deco movement, the apartment she designed for Mme Mathieu-Levy on Rue de Lota (1920-1924) was a subtle blend of simplicity, rigor, and sophistication. The space featured brick partitions, a lacquered wooden "canoe" bed, and chairs adorned with serpents.