Iturbide y Green was born in Georgetown, Washington, D.C, USA, the son of Emperor Iturbide's eldest son Ángel de Iturbide y Huarte (October 2, 1816 - July 21, 1872) and his American wife Alice Green (died 1892).
When Maximilian and Carlota took the throne of Mexico in 1863 with the support of the French troops of Napoleon III, the new monarchs invited the Iturbide family back to Mexico. As it became clear that Maximilian and Carlota could have no children together, they offered to adopt Iturbide y Green, which was agreed to with enthusiasm by his father and reluctance by his mother. They formally named Iturbide y Green their heir on September 13, 1865, with the title His Highness, Prince of Iturbide.
With the fall of the monarchy in 1867, his biological family took the child first to England and then back to the United States. When he came of age Iturbide y Green renounced all claim to any throne or title and returned to Mexico. He served as an officer in the Mexican army. After publishing articles critical of President Porfirio Díaz, he was told that he should go into exile if he valued his safety, so he returned to Georgetown, where he taught as a professor of the Spanish language and French language at Georgetown University for many years.
Agustín de Iturbide y Green died in Washington D.C. and was buried at the Church of St John the Evangelist, Philadelphia, Pennsylvania.