1828	Born in Boston, Massachusetts, son of Horace and Harriet Gray. He attended Boston schools and in 1849 graduated from Harvard College. After graduation he traveled extensively in Europe. He had been drawn first to natural history, but then settled on the law and was admitted to the Massachusetts bar in 1851.
1852-1853	Acting Reporter of Decisions during the illness of Luther Cushing. "Shortly after he was admitted to the bar, it happened that Mr. Luther S. Cushing, the reporter of decisions of our Massachusetts Supreme Court, broke down in health. He employed Mr. Gray to go on the circuit with the Judges and report the decisions. So he, in fact, prepared the final volumes of Cushing's Reports. He had already acquired a great stock of learning for a man of his age. Even then his wonderful capacity for research, the instinct which, when some interesting question of law was up, would direct his thumb and finger to some obscure volume of English reports of law or equity, was almost like the scent of a wild animal or bird of prey. He got acquainted on the circuit with all the great Massachusetts lawyers of that day -- Choate and Curtis and Bartlett and Charles Allen and Loring.... When any one of these men was arguing or was waiting to argue a great case, the young reporter would often appear to him with a case which the counsel had not discovered, and was pat to the question. So, although, he was hardly out of his boyhood, they all got to like him as a companion and to respect him as a lawyer. When Cushing died most of these leaders joined in a recommendation of Gray, who was then but twenty-six years old."1
1854	Appointed Reporter of Decisions. The Massachusetts Attorney General, addressing the court after Gray's death2, said of his work as a reporter: "This exacting work he performed with characteristic ability, leaving in every volume of the reports evidence not alone of his own increasing and accurate knowledge of the law, but illustrations of his powers of quick and complete apprehension of the issues of the causes, their reports manifesting always his wonderful lucidity and precision of statement. His notes, appended to many cases, are veritable text-books, containing great store of learning and summarizing the entire record of former adjudicated cases. They have become accepted as having almost the authority of judicial decisions. Among the many, perhaps none has proved of greater value to the profession than that of Commonwealth v. Roxbury, 75 Mass. (9 Gray) 451 (1857)"3.
1860	Retired from Reporter of Decisions position.
1864	Appointed Associate Justice of the Supreme Judicial Court. At 36 years of age, he was the youngest man in the history of the Commonwealth appointed to Massachusetts' highest court.
1873	Appointed Chief Justice of the Supreme Judicial Court.
1875	Chief Justice Gray "engaged a law clerk, a position he called 'secretary', launching a national tradition of appellate justices appointing law clerks to assist them."4 Two of his clerks were Louis Brandeis and Samuel Williston (1889) who described Justice Gray as a "charming, helpful and friendly person."5
1882	Appointed Associate Justice of the United States Supreme Court. "He was the first member of the High Court to have an official law clerk."6
1891	Presided on June 16 at the first sitting of the United States Court of Appeals for the 1st Circuit, at Boston.
1902	Died on September 15 in Nahant, Massachusetts.
1903	Justice Gray's law library sold at auction in Boston "...included 2,113 items of what had been probably the finest law library ever possessed by a United States Supreme Court Justice"7

¹ George F. Hoar, Memoir of Horace Gray, Proceedings of the Massachusetts Historical Society 162 (1904).
² 182 Mass. 613, 615 (1903).
³ Smith, John Malcolm, "Mr. Justice Horace Gray of the United States Supreme Court," 6 South Dakota Law Review 221-247 (Fall 1961).
⁴ Daniel J. Johnedis, "Creation of the Appeals Court and Its Impact on the Supreme Judicial Court" quoting Newland: "Personal Assistants to Supreme Court Justices: The Law Clerks 40 Or. L. Rev. 299, 301 n. 5 (1961) in Osgood, Russell K., "The History of Law in Massachusetts: The Supreme Judicial Court 1692-1992," Supreme Judicial Court Historical Society, Boston, Massachusetts (1992).
⁵ Mason, Brandeis: A Free Man's Life 57-58 (1946) quoted in Smith at 232.
⁶ Spector, Robert M., "Legal Historian on the United States Supreme Court: Justice Horace Gray, Jr. and the Historical Method," 12 American Journal of Legal History 181, 186 n.19 (July 1968).
⁷ Spector, Robert M., supra, p. 182 and note 5: "Justice Gray's personal library included English, Irish, Scotch, American federal and state, Canadian, and Nova Scotian reports, among others, and was worth $7,343.04, a huge sum for a personal law library at that time."