Born near McMinnville, Warren County, Tennessee, Gunter pursued classical studies and was graduated from Irving College in 1850. He studied law. He was admitted to the bar in 1853 and commenced practice in Fayetteville, Washington County, Arkansas, in 1853. During the Civil War served in the Confederate States Army as colonel of the Thirteenth Regiment, Arkansas Volunteers. He served as prosecuting attorney for the fourth judicial circuit 1866-1868. He successfully contested as a Democrat the election of William W. Wilshire to the Forty-third Congress. He was reelected to the Forty-fourth and to the three succeeding Congresses and served from June 16, 1874, to March 3, 1883. He served as chairman of the Committee on Private Land Claims (Forty-fourth through Forty-sixth Congresses). He was not a candidate for renomination in 1882. He resumed the practice of law in Fayetteville, Arkansas, and died there January 12, 1904. He was interred in Evergreen Cemetery.