Wood was elected to the Congress of the Republic of Texas in 1841, representing Liberty County in the House of Representatives. In 1845, during the annexation of Texas by the United States, he represented his home county during the convention which wrote the state constitution Wood was elected to the Texas Senate following Texas's admission to the United States. When the Mexican–American War began he resigned his senate seat and became Colonel of the Second Regiment Texas Mounted Volunteers. During his service he was present for the capture of Monterrey.