The 1782 resolution adopting the seal blazons the image on the reverse as "A pyramid unfinished. In the zenith an eye in a triangle, surrounded by a glory, proper." The pyramid is conventionally shown as consisting of 13 courses to refer to the thirteen original states. The adopting resolution provides that it is inscribed on its base with the date MDCCLXXVI (1776, the year of the United States Declaration of Independence) in Roman numerals. Where the top of the pyramid should be, the Eye of Providence watches over it. Two mottos appear: Annuit cœptis signifies that Providence has "approved of (our) undertakings." Novus ordo seclorum, freely taken from Virgil, is Latin for "a new order of the ages." The reverse has never been cut (as a seal) but appears, for example, on the back of the one-dollar bill.

The primary official explanation of the symbolism of the great seal was given by Charles Thomson upon presenting the final design for adoption by Congress. He wrote:

The pyramid signifies Strength and Duration: The Eye over it & the Motto allude to the many signal interpositions of providence in favour of the American cause. The date underneath is that of the Declaration of Independence and the words under it signify the beginning of the new American Æra, which commences from that date.

Thomson took the symbolism for the colors from Elements of Heraldry, by Antoine Pyron du Martré, which William Barton had lent him. That book said that argent (white) "signifies Purity, Innocence, Beauty, and Genteelness", gules (red) "denotes martial Prowess, Boldness, and Hardiness", and azure (blue) "signifies Justice, Perseverance, and Vigilance".

A brief and official explanation of the symbolism was prepared in the form of a historical sketch (or pamphlet) of the seal of the United States, entitled, The Seal of the United States: How it was Developed and Adopted. It was written by Gaillard Hunt in 1892 under the direction of then Secretary of State James G. Blaine. When the copyright on the pamphlet expired, Hunt expounded upon the information in more detail. This was published in 1909 in a book titled The History of the Seal of the United States. This work was largely based on a two-volume work written in 1897 by Charles A. L. Totten titled Our Inheritance in the Great Seal of Manasseh, the United States of America: Its History and Heraldry; and Its Signification unto the 'Great People' thus Sealed. Hunt's account greatly details how the seal was chosen, containing sketches of other suggestions for a great seal which were made, such as Franklin's suggested motto "Rebellion to tyrants is obedience to God", information on the illegal seal, iterations and changes that have been made t…

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On July 4, 1776, the same day that independence from Great Britain was declared by the thirteen colonies, the Continental Congress named the first committee to design a Great Seal, or national emblem, for the country. Similar to other nations, the United States needed an official symbol of sovereignty to formalize and seal (or sign) international treaties and transactions. It took six years, three committees, and the contributions of fourteen men before the Congress finally accepted a design (which included elements proposed by each of the three committees) in 1782.
The first committee consisted of Benjamin Franklin, Thomas Jefferson, and John Adams. While they were three of the five primary authors of the Declaration of Independence, they had little experience in heraldry and sought the help of Pierre Eugene du Simitiere, an artist living in Philadelphia who would later also design the state seals of Delaware and New Jersey and start a museum of the Revolutionary War. Each of these men proposed a design for the seal.

Franklin chose an allegorical scene from Exodus, described in his notes as "Moses standing on the Shore, and extending his Hand over the Sea, thereby causing the same to overwhelm Pharaoh who is sitting in an open Chariot, a Crown on his Head and a Sword in his Hand. Rays from a Pillar of Fire in the Clouds reaching to Moses, to express that he acts by Command of the Deity." Motto, "Rebellion to Tyrants is Obedience to God."

Jefferson suggested a depiction of the Children of Israel in the wilderness, led by a cloud by day and a pillar of fire by night for the front of the seal; and Hengest and Horsa, the two brothers who were the legendary leaders of the first Anglo-Saxon settlers in Britain, for the reverse side of the seal. Adams chose a painting known as the "Judgment of Hercules" where the young Hercules must choose to travel either on the flowery path of self-indulgence or the rugged, more difficult, uphill path of duty to others and honor to himself.

In August 1776, du Simitière showed his design, which was more along conventional heraldic lines. The shield had six sections, each representing "the Countries from which these States have been peopled" (using the symbols for England, Scotland, Ireland, France, Germany, and Holland), surrounded by the initials of all thirteen states. The supporters were a female figure representing Liberty holding an anchor of hope and a spear with a cap, and on the other side an American soldier holding a rifle and tomahawk. The crest was the "Eye of Providence in a radiant Triangle whose Glory extends over the Shield and beyond the Figures", and the motto E Pluribus Unum (Out of Many, One) in a scroll at the bottom.

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The Great Seal very quickly became a popular symbol of the country. It inspired both the flag of North Dakota and that of the US Virgin Islands (adopted in 1911 and 1921, respectively). Combined with the heraldic tradition of artistic freedom so long as the particulars of the blazon are followed, a wide variety of official and unofficial emblazonments appeared, especially in the first hundred years. This is evident even in the different versions of the seal die. The quality of the 1885 design, coupled with a spirit of bureaucratic standardization that characterized that era, has driven most of these out of official use.

The Great Seal symbol (or a close variant) has been used by former presidents after leaving office. In February 2021, the Seal continued to feature in the logo of the Office of Barack and Michelle Obama, and the logo of the Office of George W. Bush.