John Langdon was a Portsmouth, New Hampshire politician born on the 26th of June, 1741. Langdon was one of the early supporters of the Revolutionary War who later worked for Continental Congress. He stayed with the Congress for twelve years, and he became the Senate's first president pro tempore. After the Congress, he served as New Hampshire governor. He was nominated to be a candidate for vice presidential post in 1812, but he turned down the offer. He later retired and joined his creator on September 18, 1819.

John Langdon's father was an affluent local politician and farmer. The family had decided to emigrate to America from Sheviock, Caradon, Cornwall in 1660. The Langdon family was among the first settlers of Portsmouth which was near the mouth of Piscataqua River and one of major seaports of New England. John Langdon attended a grammar school located locally which was managed by a veteran of the siege against French in 1745 that happened in Canada Fortress Louisbourg. Finishing the primary education enabled Langdon to work as an apprentice clerk. He and his brother Woodbury Langdon, who was older than him, turned down the chance to be a part of their father's successful pursuits in the field of agriculture. Both brothers had decided to travel by sea and became apprentices to local, naval merchants.

The twenty two year old John Langdon, became the captain of Andromache, a cargo ship with destination to West Indies. After four years, he acquired his very first merchantman. Over time, he continued to own small fleet vessels, and engaged in the trade between London, Portsmouth, and the Carribean. His older brother, Woodbury, achieved more success in international trade. In the year 1770, both brothers at a young age became Portsmouth richest individuals.

Langdon's business was greatly affected when the British controlled the shipping industries, and motivated Langdon to become a prominent and ardent supporter of 1770s revolutionary movement. He served on a nonimportation committee and the New Hampshire Committee of Correspondence. During that time, he also attended many assemblies of a patriotic nature. He also took part in the confiscation and seizure from Fort William and Mary of British munitions.

During 1775 to 1776, Langdon became a member of the First Continental Congress. He resigned from his position in June, 1776. He then became an agent for the Continental forces to fight off the British, and he supervised the construction of numerous battleships including the America, the Raleigh, and the Ranger which had John Paul Jones as its captain. In 1777, the captain equipped a mission to oppose the British, participated in the Bennington Battle, and commanded Langdon's Company of Light Horse Volunteers in Rhode Island's Saratoga. In 1783, the war finally came to an end.

In 1784, the mansion named Governor John Langdon House was built in Portsmouth. In 1787, Langdon was once again a part of the Continental Congress and became a representative to the Constitutional Convention of the same year. He was elected to be a part of the U.S. Senate which he served from 1789 to 1801 in the month of March. He began his post as president pro tempore on April 6, 1789, and also served the same in the Second Congress.

Langdon also became a member of New Hampshire Legislature during 1801 to 1805, in which his last two terms he served as a speaker. He was governor from 1805 to 1811, except in 1809. In 1812, John Langdon turned down the nomination to be a vice presidential candidate and later decided to retire. He died in Portsmouth that had been his home almost all his life. The town of Langdon, New Hampshire; Langdon Street in Madison, Wisconsin; were some of the places so named in honor of the man that became an important part of a rich history.