Significance: Gray brought considerable judicial experience and wide legal learning to the Supreme Court, especially in the area of common law. Writing more than 450 Court opinions, he strongly promoted the right of states to enact legislation.
After graduating from Harvard Law School in 1851, Gray served as reporter of the Massachusetts supreme court from 1854 to 1861. He was one of the early organizers of the Free-Soil Party and later the Republican Party in Massachusetts. Frequently, he provided advice to Massachusetts governor John Andrew on legal problems arising from the Civil War. Andrew named Gray to the state supreme court in 1864, and he remained on that bench for seventeen years, serving the last eight as chief justice. Gray was appointed to the Supreme Court by President Chester A. Arthur in 1881 and was confirmed in 1882. Although often overshadowed by some better-known colleagues, he brought considerable legal experience to the Court, particularly his expertise in common law and his command of precedent. His most notable case, one of the Legal Tender Cases, was Juilliard v. Greenman (1884), which validated the continued circulation of Civil War notes. In the United States v. Wong Kim Ark (1898), Gray wrote that the Fourteenth Amendment made citizenship a birthright regardless of the race or national origin of a person who applied for naturalization.