After working his way through academy and college in Mitchell County, North Carolina, young Blalock moved to Philadelphia and secured his medical education in Jefferson Medical College of that city, graduating in March 1861.
After graduation Blalock took up the practise of medicine in Decatur, Illinois, but soon joined the 115th Illinois Volunteers as a surgeon and served with ability during the Civil War. He returned to Decatur after the war and practised his profession successfully for twelve years until 1873, when he went West with a wagon train and settled in Walla Walla, Washington. He at once established a remunerative and important practise, performing on an average a surgical operation each day and delivering during the course of his career some five thousand babies.
He was of the old-time practitioner type, seldom keeping his books in good condition, so that when he died he had over $40, 000 in outstanding bills unpaid. Nevertheless, Blalock was widely known for his interest in civic and educational affairs, serving for many years as a member of the board of trustees and later as president of the board of trustees of Whitman College. He was a member of the board of trustees of the public schools and for a number of terms mayor of his city. He aided in calling the constitutional convention of Washington in 1889, and was instrumental in framing the constitution. The death of Blalock at the age of seventy-seven closed a long career of service to his community and to the state.
From his first marriage, to Panthea A. Durham who died in 1864, there was a son who succeeded his father as a physician in Walla Walla. From a second marriage, to Marie G. Greenfield, there were two daughters.