Ector was born in Putnam County, Georgia, to Hugh and Dorothy Ector. The family moved to Greenville, Georgia, soon after. He was educated at Centre College in Danville, Kentucky, before reading for law in the office of Hiram B. Warner. Ector served a single term in the Georgia state legislature in 1842 before moving to Texas in 1850. Ector was admitted to the bar in 1851 in Henderson, Texas, and began the practice of law. That same year he married Letitia Graham, who died in 1859. In 1856 he was elected to the Texas House of Representatives from Rusk County.