Zachary Taylor was an important part of the Mexican War. He successfully defeated Mexican forces in September 1846 and allowed them two months armistice upon their retreat President James K. Polk was angry and ordered General Winfield Scott to take over and lead many of Taylor's troops into immediate action against Mexico. However, Taylor went ahead and fought Santa Anna's forces against Polk's directives. He forced Santa Anna's withdrawal and became a national hero at the same time.
Zachary Taylor was not known for his education and he had no political background. He was elected solely on his reputation as a war hero. As such, his short time in office was not one full of major accomplishments. However, if Taylor had lived and in fact vetoed the Compromise of 1850, the events of the mid-19th century would have been very different indeed.
http://www.whitehouse.gov/about/presidents/zacharytaylor
Presidentail Years: 1849-1850