During a four-decade career in public office, Woodbury served as Associate Justice of the Supreme Court of the United States, a United States Senator, the ninth governor of New Hampshire, and cabinet member in the Andrew Jackson and Martin Van Buren administrations.

He served another term representing New Hampshire in the Senate from 1841 to 1845, when he accepted President James K. Polk's appointment to the Supreme Court.

During his time in Francestown, he wrote the Hillsborough Resolves to defend the Madison administration for their decisions in the War of 1812, which marked the beginning of his political involvement.

Following the publication of his defense, he gained the recognition he needed to receive an appointment as clerk of the New Hampshire State Senate from 1816 to 1817.

At the beginning of this term, he was instrumental in the appointment of fellow New Hampshireman Edmund Roberts as special agent and envoy to the Far East.

It was largely repealed under the new administration the following year, but the foundation was laid for an independent U.S. Treasury, finally established in 1846, under President James K. Polk.

In that year, Woodbury also delivered a Phi Beta Kappa Address at his alma mater, Dartmouth College, titled "Progress.

On September 20, 1845, Polk gave Woodbury a recess appointment as an associate justice of the United States Supreme Court,[7] to a seat vacated by Joseph Story.

He wrote of the judicial powers: In due time, by stopping the fountain-head of slavery, through the power expressly granted to Congress to prohibit further additions to it from abroad ... the country will be enabled gradually to purify the corrupt waters that have flowed from this fountain ... if all this should be accomplished without violating the sacred compromises of the constitution.

Although Woodbury had already died when the Court decided Dred Scott v. Sandford (1857), he set a precedent when he wrote for the majority in Jones v. Van Zandt (1847).

Woodbury ruled in favor of the rights of slaveholders by arguing that the compromises in the US Constitution, such as the Fugitive Slave Clause, bound the states to enforce the act.

It also furthered the precedent established in Prigg v. Pennsylvania that the Fugitive Slave Act was constitutional and paved the way for the Dred Scott decision.

The issue the Court had to decide was "whether an act of the legislature of Mississippi... impaired the obligation of any contract which the state or others had previously entered into with Planters' Bank.

"[10] Woodbury ruled in favor of the bank and found that the Mississippi statute violated the Contract Clause in Article 1, Section 10, of the US Constitution.

Woodbury also formed the basis for the interpretation of the Commerce Clause in the License Cases in which he developed a case-by-case method for determining the extent of state regulatory power.

Lacking a clear precedent for how much power the states had under the Constitution to regulate commerce, the justices were not unified enough to write a majority opinion.

Woodbury's opinion focused on the context on a case-by-case basis instead of deciding based on an abstract principle of commerce power.

The Court later followed Woodbury's reasoning in Cooley v. Board of Wardens that it would decide on a case-by-case basis depending on whether the subject of regulation was local in nature or required national legislation.

Woodbury's contributions to the interpretation of the Commerce Clause extended to a defense of states' rights in Waring v. Clarke.