Benjamin Blackwell attended the Medical College of Virginia, graduating in 1903 with the degree of D.D.S. (Doctor of Dental Science). He practiced in Richmond where he lived on Monument Avenue. A democrat, Dr. Blackwell attended Grove Avenue Church and served as deacon for four years. Also, he was a Mason, belonged Chi Psi Phi, a dental Greek fraternity, the Westmoreland Club, Richmond City Central Society (president in 1914), the Virginia State Dental Association (president in 1920), and the American Dental Association. He also served as a member of the Virginia State Board of Dental Examiners for three years, 1923-1926.

During the Spanish American War, Benjamin Blackwell was a private in Co. H of the 2nd Regiment of the Georgia Infantry. He was in camp in Tampa, Florida, and spent time at the Fort McPherson Hospital with typhoid fever. He was discharged 8 Dec 1898 at Rome, Georgia, signed by Capt. Walter Perkins (Capt. Co. H, 2nd Ga. Vol. Inf.).592