After the war's conclusion, Holmes returned to Harvard to study law. He was admitted to the bar in 1866, and went into practice in Boston. He joined a small firm, and married a childhood friend, Fanny Bowditch Dixwell. Their marriage lasted until her death on April 30 1929. They never had children together. They did adopt and raise an orphaned cousin, Dorothy Upham. Mrs. Holmes was described as devoted, witty, wise, tactful, and perceptive.
Whenever he could, Holmes visited London during the social season of spring and summer. He formed his closest friendships with men and women there, and became one of the founders of what was soon called the “sociological” school of jurisprudence in Great Britain, which would be followed a generation later by the “legal realist” school in America.
Holmes practiced admiralty law and commercial law in Boston for fifteen years. In 1870, Holmes became an editor of the American Law Review, edited a new edition of Kent's Commentaries on American Law, and published numerous articles on the common law. In 1881, he published the first edition of his well-regarded book The Common Law, in which he summarized the views developed in the preceding years. This remains the only important work of American jurisprudence written by a practicing attorney. In the book, Holmes sets forth his view that the only source of law, properly speaking, is a judicial decision. Judges decide cases on the facts, and then write opinions afterward presenting a rationale for their decision. The true basis of the decision, however, is often an "inarticulate major premise" outside the law. A judge is obliged to choose between contending legal theories, and the true basis of his decision is necessarily drawn from outside the law. These views endeared Holmes to the later advocates of legal realism and made him one of the early founders of law and economics jurisprudence.
Holmes was considered for a judgeship on a federal court in 1878 by President Rutherford B. Hayes, but Massachusetts Senator George Frisbie Hoar convinced Hayes to nominate another candidate. In 1882, Holmes became both a professor at Harvard Law School and then a justice of the Supreme Judicial Court of Massachusetts, resigning from the law school shortly after his appointment. He succeeded Justice Horace Gray, whom Holmes coincidentally would replace once again when Gray retired from the U.S. Supreme Court in 1902. In 1899, Holmes was appointed Chief Justice of the court.
During his service on the Massachusetts court, Holmes continued to develop and apply his views of the common law, usually following precedent faithfully. He issued few constitutional opinions in these years, but carefully developed the principles of free expression as a common-law doctrine. He departed from precedent to recognize workers' right to organize trade unions as long as no violence or coercion was involved, stating in his opinions that fundamental fairness required that workers be allowed to combine to compete on an equal footing with employers.
Holmes was known for his pithy, short, and frequently quoted opinions. In more than thirty years on the Supreme Court bench, he ruled on cases spanning the whole range of federal law. He is remembered for prescient opinions on topics as widely separated as copyright, the law of contempt, the antitrust status of professional baseball, and the oath required for citizenship. Holmes, like most of his contemporaries, viewed the Bill of Rights as codifying privileges obtained over the centuries in English and American law. Beginning with his first opinion for the Court, in Otis v. Parker, Holmes declared that "due process of law," the fundamental principle of fairness, protected people from unreasonable legislation, but was limited to only those fundamental principles enshrined in the common law and did not protect most economic interests. In a series of opinions during and after the First World War, he held that the freedom of expression guaranteed by federal and state constitutions simply declared a common-law privilege to do harm, except in cases where the expression, in the circumstances in which it was uttered, posed a "clear and present danger" of causing some harm that the legislature had properly forbidden. In Schenck v. United States, Holmes announced this doctrine for a unanimous Court, famously declaring that the First Amendment would not protect a person "falsely shouting fire in a theatre and causing a panic."
The following year, in Abrams v. United States, Holmes — influenced by Zechariah Chafee's article “Freedom of Speech in War Time” — delivered a strongly worded dissent in which he criticized the majority's use of the clear and present danger test, arguing that protests by political dissidents posed no actual risk of interfering with war effort. In his dissent, he accused the Court of punishing the defendants for their opinions rather than their acts. Although Holmes evidently believed that he was adhering to his own precedent, many later commentators accused Holmes of inconsistency, even of seeking to curry favor with his young admirers. The Supreme Court departed from his views where the validity of a statute was in question, adopting the principle that a legislature could properly declare that some forms of speech posed a clear and present danger, regardless of the circumstances in which they were uttered.
Holmes was criticized during his lifetime and afterward for his philosophical views, which his opponents characterized as moral relativism. Holmes's critics believe that he saw few restraints on the power of a governing class to enact its interests into law. They assert that his moral relativism influenced him not only to support a broad reading of the constitutional guarantee of "freedom of speech," but also led him to write an opinion for the Court upholding Virginia's compulsory sterilization law in Buck v. Bell, 274 U.S. 200 (1927), where he found no constitutional bar to state-ordered compulsory sterilization of an institutionalized, allegedly "feeble-minded" woman. Holmes wrote ,"It is better for all the world, if instead of waiting to execute degenerate offspring for crime or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind . . . three generations of imbeciles are enough." While his detractors points to this case as an extreme example of his moral relativism, other legal observers argue that this was a consistent extension of his own version of strict utilitarianism, which weighed the morality of policies according to their overall measurable consequences in society and not according to their own normative worth.
Holmes was admired by the Progressives of his day who concurred in his narrow reading of "due process." He regularly dissented when the Court invoked due process to strike down economic legislation, most famously in the 1905 case of Lochner v. New York. Holmes's dissent in that case, in which he wrote that "a Constitution is not intended to embody a particular economic theory," is one of the most-quoted in Supreme Court history. However, Holmes wrote the opinion of the Court in the Pennsylvania Coal v. Mahon case which inaugurated regulatory takings jurisprudence in holding a Pennsylvania regulatory statute constituted a taking of private property. His dissenting opinions on behalf of freedom of expression were celebrated by opponents of the Red Scare and prosecutions of political dissidents that began during World War I. Holmes's personal views on economics were influenced by Malthusian theories that emphasized struggle for a fixed amount of resources, however, he did not share the young Progressive's ameliorist views.
Holmes served on the court until January 12, 1932, when his brethren on the court, citing his advanced age, suggested that the time had come for him to step down. By that time, at 90 years of age, he was the oldest justice to serve in the court's history. Three years later, Holmes died of pneumonia in Washington, D.C. in 1935, two days short of his 94th birthday. In his will, Holmes left his residuary estate to the United States government (he had earlier said that "taxes are the price we pay for a civilized society"). He was buried in Arlington National Cemetery, and is commonly recognized as one of the greatest justices of the U.S. Supreme Court.
Holmes's papers, donated to Harvard Law School, were kept closed for many years after his death, a circumstance that gave rise to numerous speculative and fictionalized accounts of his life. Catherine Drinker Bowen's fictionalized biography "Yankee from Olympus" was a long-time bestseller, and the 1951 Hollywood motion picture The Magnificent Yankee was based on a highly fictionalized play about Holmes's life. Since the opening of the extensive Holmes papers in the 1980s, however, there has been a series of more accurate biographies and scholarly monographs.
Holmes is featured in the following passage by Isaac Asimov:
Holmes, in his last years, was walking down Pennsylvania Avenue with a friend, when a pretty girl passed. Holmes turned to look after her. Having done so, he sighed and said to his friend, "Ah, George, what wouldn't I give to be seventy-five again?