The facade of the four-story base is composed of limestone and Texas pink granite.
It includes bronze grilles as well as sculptures depicting industrial progress.
There is a clock atop the base, located 64 feet (20 m) above the ground with a diameter of 9 feet (2.7 m).
The clock is flanked by a figure of the god Mercury on the left, representing transportation, and a figure of the goddess Ceres on the right, representing Industry.
The composition measures 19 feet (5.8 m) tall by 45 feet (14 m) wide and was designed by Edward McCartan.
The windows on the base contain one of four types of display-window designs: the original designs installed with the rest of the building in 1929, and one of three modifications.

The upper stories are faced with brick.
The northern facade of the fifth through 15th stories curve along the wings.
The facade of this section contains paired sash windows with decorative metal spandrels, as well as limestone keystones above the windows on the 15th story.
Above the 15th floor is a cornice with 78 terracotta bison heads, which symbolize industry.
The cornice also contains images of Mercury's winged helmet, winged wheels representing advancement, scrolls of wisdom, wheels of progress, and other motifs.
The 15th story of the eastern facade had a sky bridge that connected to 466 Lexington Avenue until the bridge was demolished in 1982.

The 16th through 35th-story facades contain identical decorative elements on all sides.
Like the lower stories, these are faced with brick and contain paired sash windows.
Above the 28th floor are limestone keystones over the windows, as well as a cornice with brackets.
There is an ornate entablature above the 31st floor; keystones above the 32nd-floor windows; bracketed keystones above the 33rd floor windows; and an observation deck on the 33rd floor.
The last full floor, the 34th floor, has three pairs of windows on all sides, protruding from the roof as dormers.

The top of the Helmsley Building is a pyramid and capped by an ornate cupola.
The roof was lit at night by electric floodlights and torches with up to 100,000 candlepower.
At the pinnacle were "32-marine-type fixtures" that each had a capacity of up to 100 watts.
The cupola had oval openings and was topped by a glass ball with a 6,000 watt lantern.
Eight projectors, one from each corner of the octagon's base, also illuminated the roof.
The lighting made the Helmsley Building into a point of interest that could be seen from several miles away.
When the Helmsley Building was completed, the copper roof was gilded, but by the late 1950s had been painted green.
The gilding was restored in the 1970s and removed in 2002.
The facade of the four-story base is composed of limestone and Texas pink granite. It includes bronze grilles as well as sculptures depicting industrial progress. There is a clock atop the base, located 64 feet (20 m) above the ground with a diameter of 9 feet (2.7 m). The clock is flanked by a figure of the god Mercury on the left, representing transportation, and a figure of the goddess Ceres on the right, representing Industry. The composition measures 19 feet (5.8 m) tall by 45 feet (14 m) wide and was designed by Edward McCartan. The windows on the base contain one of four types of display-window designs: the original designs installed with the rest of the building in 1929, and one of three modifications.
The upper stories are faced with brick. The northern facade of the fifth through 15th stories curve along the wings. The facade of this section contains paired sash windows with decorative metal spandrels, as well as limestone keystones above the windows on the 15th story. Above the 15th floor is a cornice with 78 terracotta bison heads, which symbolize industry. The cornice also contains images of Mercury's winged helmet, winged wheels representing advancement, scrolls of wisdom, wheels of progress, and other motifs. The 15th story of the eastern facade had a sky bridge that connected to 466 Lexington Avenue until the bridge was demolished in 1982.
The 16th through 35th-story facades contain identical decorative elements on all sides. Like the lower stories, these are faced with brick and contain paired sash windows. Above the 28th floor are limestone keystones over the windows, as well as a cornice with brackets. There is an ornate entablature above the 31st floor; keystones above the 32nd-floor windows; bracketed keystones above the 33rd floor windows; and an observation deck on the 33rd floor. The last full floor, the 34th floor, has three pairs of windows on all sides, protruding from the roof as dormers.
The top of the Helmsley Building is a pyramid and capped by an ornate cupola. The roof was lit at night by electric floodlights and torches with up to 100,000 candlepower. At the pinnacle were "32-marine-type fixtures" that each had a capacity of up to 100 watts. The cupola had oval openings and was topped by a glass ball with a 6,000 watt lantern. Eight projectors, one from each corner of the octagon's base, also illuminated the roof. The lighting made the Helmsley Building into a point of interest that could be seen from several miles away. When the Helmsley Building was completed, the copper roof was gilded, but by the late 1950s had been painted green. The gilding was restored in the 1970s and removed in 2002.
Helmsley Building