The Moongate Garden, designed by architect Jean Paul Carlhian, was inspired by the gardens and architecture of the Temple of Heaven in Beijing, China. The Temple of Heaven was designed using a geometrical, axial layout, centered around the cardinal points of the compass. The garden is meant to take its visitors to a relaxing place usually surrounded by water where they may absorb the cool air emanating from the water.

Granite and water are used abundantly in the Moongate Garden; water in fact is the dominant feature. Rocks and water in Chinese culture symbolize the basic constituents of nature. Rock is thought to symbolize the body of the earth while water symbolizes the spirit thereof. The water's reflection gives the garden the appearance of being larger than it actually is. It gives off shimmering light effects in the sunlight and reflects the glow of the moon at night.

The overall circular pool design of the Moongate Garden is meant to remind us of the windows in the Arthur M. Sackler Gallery, a technique that Carlhian also applied to the Fountain Garden. The path leading into the Moongate Garden enters at the southwest corner and exists at the northeast corner. Carlhian call this the "pinwheel treatment" and utilized it to align important features of the Arts and Industries Building with the Freer Gallery

The garden near the Sackler Gallery feature two 9-foot-tall pink granite moon gates on either side of a pool that is paved with half-round pieces of granite. Two more gates are laid flat to provide seating in opposite corners. The gates are strategically placed to frame important features of the surrounding landscape. This is intended to be a sunny garden that is enjoyed by visitors on cooler days.