Marshall first left home for any length of time to serve as an officer in the American Revolution. He returned in 1779 after attending for a few months lectures on law given by George Wythe at the College of William and Mary (his only formal education). Admitted to the bar in 1780, he practiced law in the West and was elected (1782) a delegate to the Virginia assembly. He married and settled in Richmond, his home until his death.

His brilliant skill in argument made him one of the most esteemed of the many great lawyers of Virginia. A defender of the new U.S. Constitution at the Virginia ratifying convention, Marshall later staunchly supported the Federalist administration, and after refusing Washington's offer to make him U.S. Attorney General or minister to France, he finally accepted appointment as one of the commissioners to France in the diplomatic dispute that ended in the XYZ Affair.

Marshall's effectiveness there made him a popular figure, and he was elected to Congress as a Federalist in 1799. One of the tiny group that continued to support President John Adams, he was prevailed upon to become Secretary of State (1800-1801). Before he left the cabinet he was appointed chief justice and confirmed by the Senate despite some opposition.

In his long service on the bench, Marshall raised the Supreme Court from an anomalous position in the federal scheme to power and majesty, and he molded the Constitution by the breadth and wisdom of his interpretation; he eminently deserves the appellation the Great Chief Justice. He dominated the court equally by his personality and his ability, and his achievements were made in spite of strong disagreements with Jefferson and later Presidents.

A loyal Federalist, Marshall saw in the Constitution the instrument of national unity and federal power and the guarantee of the security of private property. He made incontrovertible the previously uncertain right of the Supreme Court to review federal and state laws and to pronounce final judgment on their constitutionality. He viewed the Constitution on the one hand as a precise document setting forth specific powers and on the other hand as a living instrument that should be broadly interpreted so as to give the federal government the means to act effectively within its limited sphere (see McCulloch v. Maryland).

His opinion in the Dartmouth College Case was the most famous of those that dealt with the constitutional requirement of the inviolability of contract, another favorite theme with Marshall. His interpretation of the interstate commerce clause of the Constitution, most notably in Gibbons v. Ogden, made it a powerful extension of federal power at the expense of the states. In general Marshall opposed states' rights doctrines, and there were many criticisms advanced against him and against the increasing prestige of the Supreme Court.

The sometimes undignified quarrel with Jefferson (which had one of its earliest expressions in Marbury v. Madison) reached a high point in the trial (1807) of Aaron Burr for treason. Marshall presided as circuit judge and interpreted the clause in the Constitution requiring proof of an "overt act" for conviction of treason so that Burr escaped conviction because he had engaged only in a conspiracy. Marshall's difficulties with President Jackson reached their peak when Marshall declared against Georgia in the matter of expelling the Cherokee, a decision that the state flouted.

Marshall in his arguments drew much from his colleagues, especially his devoted adherent, Justice Joseph Story, and he was stimulated and inspired by the lawyers pleading before the court, among them some of the most brilliant legal minds America has seen, including Daniel Webster, Luther Martin, William Pinkney, William Wirt, and Jeremiah Mason. Marshall in his manners combined the unceremonious heartiness of the frontier with the leisurely grace of the Virginia aristocracy. So great was his winning charm and so absolute his integrity that he gained the admiration of his enemies and the unbounded affection of his friends.

His style combined conciseness and precision. He wrote each opinion as a series of logical deductions from self-evident propositions, and it was almost never his practice to cite legal authority. It is in these opinions that his literary skill is shown rather than in his major nonlegal work, The Life of George Washington (5 vol., 1804-7). Marshall's constitutional opinions are collected in editions by J. M. Dillon (1903) and J. P. Cotton (1905). An autobiographic sketch was published in 1937.