Teunis Van Vechten,was born in 1785. He graduated from Union College in 1802, and studied law with his uncle Abraham Van Vechten. After being admitted to the bar in 1806, he joined his uncle and later succeeded to his practice, representing the Van Rensselaer patroonship. He had a long and distinguished legal and civic career, spanning nearly five decades.
In addition to his uncle, Teunis Van Vechten practiced with several other noted attorneys, including Ebenezer Baldwin, John Davis, Judge Daniel Cady, Samuel Wilkeson, Col. Duncan Mc Martin and Charles M. Jenkins. He was known as a strong practical lawyer of sound judgment and scrupulous integrity. Van Vechten possessed a deep sense of civic duty in his native city, having served as Mayor of Albany for four terms. He also served as Alderman. He was the trustee of Albany Academy, director of the Bank of Albany and the Albany Insurance Company.
In 1850, he was disabled by a severe stroke and retired from the practice of law. He died in 1859, and was eulogized by Rev. E. P. Rogers in the published treatise The Strong Staff Broken: a discourse in memory of Hon. Teunis Van Vechten: pronounced Sunday February 13, 1859.