Teunis G. Bergen was born in the town of New Utrecht, New York on October 6, 1806, the eldest child of Garret Bergen and his wife Jane (nee Wyckoff). While growing up, he worked on his father's farm in the Gowanus area of Brooklyn and was educated at both the common school of the district and at Erasmus Hall Academy in Flatbush. As a young man, he was trained as a surveyor and subsequently pursued a successful career in this field.

Bergen was also a farmer and an active civic leader. As a member of the 241st regiment of the New York State Militia, he held the ranks of Ensign, Captain, Adjutant, Lieutenant-Colonel, and finally, Colonel. He served on the Kings County Board of Supervisors as the Supervisor of the town of New Utrecht for twenty-three years, 1836-1859, and was Chairman of the Board from 1842 to 1846. Bergen served as a member of the New York State Constitutional Conventions of 1846, 1867, and 1868, and was a delegate to the National Democratic Convention of 1860. In 1864, he was elected to the United States House of Representatives as a Democrat to the Thirty-ninth Congress, an office which he held until 1867.

In addition to his professional and civic activities, Teunis G. Bergen was a self-trianed historical researcher and genealogist, as well as a published author. His genealogical interests included not only his own family, but also many other prominent Brooklyn families. His published works include The Register of the Early Settlers and Freeholders of Kings County, NY, from its First Settlement by Europeans, to 1700, with Biographical Notices and Family Genealogies; Genealogy of the Van Brunt Family, 1653-1867; The Bergen Family; or, the Descendents of Hans Hansen Bergen, One of the Early Settlers of New York and Brooklyn, L.I., with Notes on the Genealogy of Some of the Branches of the Cowenhoven, Voorhees, Eldert, Stoothoof, Cortelyou, Stryker, Suydam, Lott, Wyckoff, Barkeloo, Lefferts, Martense, Hubbard, Van Brunt, Vanderbilt, Vanderveer, Van Nuyse, and Other Long Island Families; Genealogy of the Lefferts Family, 1650-1878; and his seven volume A History of New Utrecht, Long Island. Additionally, he contributed frequently to the New York Genealogical and Biographical Record.

Teunis G. Bergen died of pneumonia at his residence in New Utrecht, Long Island at the age of 74, and was interred at Green-Wood Cemetery.

The Bergen family that settled and proliferated throughout New York and New Jersey beginning in the 17th century is descended from the common ancestor, Hans Hansen Bergen, a native of Bergen, Norway. A ship's carpenter by trade, Bergen moved to Holland as a young man, and subsequently emigrated to the colony of New Amsterdam in 1633. His name appeared in land and church records in different forms, including Hans de Boer, Hans Noorman, Hans Hanszen Van Bergen, Hans Hansen, and Hans Hansen Bergen. It was not until the late 17th or early 18th century that his descendents formally adopted the surname, Bergen.

In 1639, Hans Hansen Bergen married Sara Rapalje, who was mistakenly rumored to have been the first European child born in the colony of New Netherland. They had eight children, among them Michael Hansen Bergen (baptized November 4, 1646), who held civil office for several years and was one of the patentees named in Governor Thomas Dongan's patent of May 13, 1686, which provided the land grant that established the village of Breuklen in the colony of New York. He and his wife, Femmetje Bergen (nee Theunis) had five children.

Michael Hansen Bergen's son, Hans Michielzse Bergen (baptized March 11, 1689) was a baker who resided near Brooklyn Ferry with his wife, Rachel (nee Bensing or Benson). They had seven children, among them Tunis Bergen (baptized October 15, 1730), who held civil and military office in Brooklyn. Tunis and his wife, Johanna (nee Stoothoff) had nine children, including their son, Garret Bergen.

Garret Bergen (born January 11, 1772) held civil and church office in Brooklyn, and was married to Jane Wyckoff on January 6, 1806. Together they had eleven children, including their first born, Teunis G. Bergen, who was born on October 6, 1806.