Theodore was a son of Julius E. and Nancy Ann Willis Davisson. He married Elisabeth J. Burnside on April 20, 1854. He was a farmer and a carpenter. He joined the Union side in the Civil War and served the last nine months under Capt. John T. Drake, Company G, 6th Regiment of the West Virginia Infantry. During his service he developed what would be diagnosed as muscular rheumatism. He was granted a disability pension. He died of cancer at the age of 83. Elisabeth died in 1912.