The Museum’s 85,000-square-foot building was designed by the architectural firm Ladd & Kelsey for the Pasadena Art Museum. The modernist building features rounded walls, an irregular H-shaped layout and an exterior clad in approximately 115,000 tiles designed by Edith Heath of Heath Ceramics. Since the Norton Simon Museum’s establishment, the interior of the building has been adapted to better complement Norton Simon’s collections. As early as 1974, the architect Craig Ellwood erected large partitions in the galleries to expand the available wall space for works on paper and to provide a backdrop for the sculpture collection. Twenty years later, in 1995, the Board of Trustees and Norton Simon’s widow, Jennifer Jones Simon, enlisted architect Frank O. Gehry to completely renovate the Museum’s interior. Gehry added skylights to the main galleries, raised the ceilings, squared off curved walls and divided the wings into more intimate rooms. The lower-level galleries were transformed to provide a harmonious space for South and Southeast Asian sculpture and a dedicated location for rotating exhibitions.

Alongside Gehry’s renovations to the galleries, landscape designer Nancy Goslee Power reimagined the Sculpture Garden. Taking inspiration from Claude Monet’s property in Giverny, France, Power replaced the rectangular reflecting pool with an organically shaped pond. She added several varieties of water lilies to the pond’s surface, while planting iris, daylily, lavender and yellow bells around its edge. A footpath was laid across the grounds, enabling visitors to discover sculptures by such artists as Henry Moore, Barbara Hepworth and Aristide Maillol. Historic plants from the original site were maintained in Power’s design, including the grove of eucalyptus, the Moreton Bay fig and the large coral tree near the rear of the pond. At the entrance to the Museum, Power and Museum curators installed sculptures by Auguste Rodin under a canopy of Mexican sycamores.