Temple Emanu-El was designed and built by the leading craftsmen of the era, utilizing the finest materials from around the world. The architectural firm headed by Robert D. Kohn, Charles Butler, and Clarence Stein led the team that also included the firms of Goodhue Associates and Mayers, Murray & Phillip. Hildreth Meière created the designs for the great mosaic arch in the Sanctuary, and Heinigke & Smith developed those for the Beth-El Chapel. Ornamental metal includes the work of Oscar Bach and Samuel Yellin. Carvings, which grace the column capitals, balcony, and the pulpits, were done by Ulysses Ricci.

The Temple's floor plan and long-span steel structure create a breathtaking interior space: 147 feet long, 77 feet wide, and 103 feet high, with a seating capacity of 2,500. The vast clear span is achieved by structural steel roof trusses and steel piers.

The Temple sits on Fifth Avenue and faces Central Park with a limestone façade dominated by a monumental recessed arch. This arch contains the stunning stained-glass rose window, a six-pointed Star of David at its center, created by Oliver Smith. The 12 spokes represent the Tribes of Israel, a motif that is echoed in the Temple's enormous bronze entrance doors. The four lancet windows, representative of the Matriarchs, are filled with biblical symbols including David's harp, the staff of Moses entwined with a serpent, and the Garden of Eden. The 18 elongated ovals that frame the window suggest the 18-part daily prayer (amidah) as well as the numerical equivalent of the Hebrew word for life (chai). The seven narrow arched windows above correspond to the seven days of creation, while the colored-glass segments within and around the spokes contain designs of abstract flower-like forms.

A richly decorated version of the arch is repeated at the bimah at the east end of the Sanctuary. The Torah Ark, choir loft, and organ screen are set within this arch, filling the entire eastern wall (which faces Jerusalem). Each side of the Sanctuary is punctuated with five massive, recessed arches lit by stained-glass windows. The more intimate Beth-El Chapel incorporates above its Ark a delicate stained-glass Tiffany window from the earlier Emanu-El sanctuary at 43rd Street.

The architecture of the vast interior, the vibrant patterns of the ceiling, and the array of materials form a masterful composition with reliance on lavish ornamentation. The richness of the colored light flowing from the stained glass, the soft tonality of the sound-absorbing Guastavino Akoustalith tile walls, the jewel-toned geometric patterns in the ceiling, and the sparkling colors and gold reflecting off the variegated mosaic tiles around the arch all harmonize to fill the spacious Sanctuary with a sense of majesty and awe.