John Marshall was sworn in as the Chief Justice on February 4, 1801, during a contentious political climate in which Federalists and Democratic-Republicans were vying for power. He had been nominated by outgoing President John Adams, a Federalist, who sought to secure a legacy for his party before leaving office. Marshall's ascendance to the highest judicial position ensured that Federalist principles would influence the judicial landscape even as the incoming Jefferson administration, led by the Democratic-Republicans, aimed to roll back Federalist policies.

As Chief Justice, Marshall presided over landmark cases that significantly shaped American law, including Marbury v. Madison, which established the principle of judicial review. This principle empowered the Supreme Court to invalidate laws and executive actions deemed unconstitutional, effectively positioning the judiciary as a co-equal branch of government alongside the executive and legislative branches.

The swearing-in ceremony took place at the U.S. Capitol, then located in Philadelphia, which was the temporary capital of the United States before Washington, D.C., was fully established. Marshall's tenure would not only transform the Supreme Court but would also solidify its role in interpreting the Constitution, pushing the United States toward a more centralized federal government. His commitment to a strong national government was influential in shaping future judicial decisions and the balance of power within the federal system.