The most relevant aspect of Ruffin's life was his time as a Justice on the North Carolina Supreme Court and the opinions which he issued from that position which have been cited in many instances as precedent setting, even in other jurisdictions. Roscoe Pound, dean of Harvard Law School, called Ruffin "one of the ten greatest jurists in American history."
He is perhaps best known for his opinion in the case of North Carolina vs. Mann, involving the shooting of a slave by the person to whom she had been rented out. Ruffin held in his opinion that in order for the submission of a slave to be perfect, then the authority of the master must be absolute, including the power of life and death. There is some argument that Ruffin had personal qualms about the decision; however he believed that this was the proper interpretation of the law, and so held.