Who was the American Commander who led the invasion of Mexico from Texas and brought about the defeat of Mexico City?

Answer 1

There wasn't any. Zachary Taylor invaded Mexico from the North, but did not reach Mexico City. A second American army led by Winfield Scott landed on the port of Veracruz, some 250 miles East of Mexico City. Scott then reputedly followed the same route used by conquistador Hernán Cortés to reach the Mexican capitalm built on the ruins of the former Aztec city of Tenochtitlán. It was Scott who occupied Mexico City and brought about the defeat of Mexico, not quite as a city but as a country. Nonetheless, Mexican government officials as a whole never fell prisoners to Scott. Mexican seat of government was moved to the town of Guadalupe, a few miles North of Mexico City proper, in the aftermath of the battle of Chapultepec, the last Mexican stronghold keeping Scott from occupying the city. It was in that town of Guadalupe that a treatise was signed between both governments, whereby American armies left Mexican territory in exchange for Mexico giving up the territories which these days make up all of California, Nevada and Utah, and most of Colorado, Arizona and New Mexico. A sum of money paid by the United States to Mexico was also part of the settlement. At that time, Texas was already an American state. It was, in fact, Texan decision to become part of the United States instead of carrying on as an independent republic which caused the Mexican American war in the first place.