Late in 1821, Agustín de Iturbide, was proclaimed emperor first by the people and then by the Supreme Congress, officially as a temporary measure until a member of European royalty could be persuaded to become monarch of Mexico. In 1823, a revolt against Iturbide established the United Mexican States.

It was readopted from 1867-1881 when the Mexican Republic was reestablished after Maximilian's reign.

The Habsburg Archduke Ferdinand Maximilian of Austria and his wife Belgian wife Carlota, a cousin of Queen Victoria of the United Kingdom, were placed on the throne of Mexico as Emperor Maximilian I and the Empress Carlota of Mexico. They ruled with support of the French occupational forces, the Roman Catholic clergy, conservative elements of the upper class, and some indigenous communities. Although the French, then considered one of the most efficient armies of the world, suffered an initial defeat in the Battle of Puebla in 1862 (now commemorated as the Cinco de Mayo holiday), they eventually defeated the Mexican government forces led by General Ignacio Zaragoza and set the couple upon the throne.

In the election of 1876, Lerdo was re-elected, defeating his opponent Porfirio Díaz. After the election, Díaz rebelled against the government and managed to overthrow Lerdo, who fled the country. Díaz became the new president. Thus began a period of more than thirty years (1876-1911) during which Díaz was the strong man in Mexico.

In 1880, President Porfirio Díaz decided that the eagle should display wings, following the French trend, and no crown. This design was adopted by decree on December 20, 1880, and used a design by Tomás de la Peãta, a well-known and popular Mexican painter of this time period.

During this period of Porfirio Díaz poorly disguised dictatorship, the country's infrastructure improved greatly thanks to increased foreign investment, but the period is also characterized by social inequality and discontent among the working classes. In 1910, the 80-year-old Díaz decided to hold an election to serve another term as president. When the official election results were announced, it was declared that Díaz had won re-election almost unanimously, with his opponent receiving only a few hundred votes in the entire country. This fraud by Díaz was too blatant for the public to swallow, and riots broke out starting the Mexican Revolution.

Venustiano Carranza was Senator for his native State during Porfirio Díaz's dictatorship. Through the proclamation of the Plan of Guadalupe in 1913, Carranza proclaimed himself as Chief of the Constitutionalist Army, as an effort to restore order to the boiling country. After several victorious battles, Carranza and his army entered Mexico City on August 20, 1914. In 1917, the Constitución Política de los Estados Unidos Mexicanos (Political Constitution of the Mexican United States), was proclaimed and still remains in effect today.

The new design had the same elements of the traditional Mexican Coat of Arms: eagle, snake, nopal, stone, garland and ribbon, but the eagle is bending over, showing its left profile, had its head bowed with the wings expanded down, and the tail expanded and higher than its predecessor. The nopal was made up with nine leaves, thus adding three more than the former one. This design was created by the artists Antonio Gómez and Jorge Enciso.

In 1918, President Venustiano Carranza had reversed the changes made by Díaz, and restored some of the original Aztec symbols. In this version the water snake was replaced with a rattlesnake, and the eagle was seen in a side view instead of a front view.

This is now the present version of the Mexican Shield and Coat-of-Arms and is used on the national flag on land as the civil, state and war flag, and at sea as the naval ensign.