Answer by taking a quote from the following article:

Sam Houston was the fifth son of Major Samuel Houston and Elizabeth Paxton. Houston's paternal ancestry is often traced to his great-great grandfather Sir John Houston, who built a family estate in Scotland in the late seventeenth century. His second son John Houston emigrated to Ulster, Ireland, during the Ulster plantation period. Under the system of primogeniture, he did not inherit the estate.

Houston was twice elected President of the Republic of Texas. In the 1836 election, he defeated Stephen F. Austin and Henry Smith with a landslide of over 79% of the vote. Houston served from October 22, 1836, to December 10, 1838. The Constitution of the Republic of Texas stated that no president could succeed himself, but did not prohibit any non-consecutive multiple terms.  When his first term ended, he was elected to serve as a representative from San Augustine County in the Republic of Texas House of Representatives. After his term as representative ended, Houston again served as President of the Republic of Texas from December 12, 1841, to December 9, 1844.  While he initially sought annexation by the U.S., Houston dropped that goal during his first term. In his second term, he strove for fiscal prudence and worked to make peace with the various tribes of Native Americans in the Republic. He also struggled to avoid war with Mexico, whose forces invaded twice during 1842. In response to the Regulator-Moderator War of 1844, he sent in Republic militia to put down the feud.  Houston still believed that the U.S annexation of Texas was not a realistic goal and the U.S. Senate would never pass it because of the delicate situation between the recently independent Texas and Mexico. However, Houston was a politician and as such he sought to preserve his career by endorsing the support of annexation into the U.S. Without his endorsement, the Texas congress would have put the question to public election and upon its likely passing would have effectively destroyed Houston's career as a Texas politician. To help save his political reputation, Houston sent James Pinckney Henderson to Washington to help Isaac Van Zandt advocate the annexation of Texas.

Anything else interesting?
He also struggled to avoid war with Mexico, whose forces invaded twice during 1842.