William H. Van Schoonhoven graduated from Union College in 1829.
On September 1, 1834, he married Margaret Brinkerhoff (1818–1897), and their daughter was Phoebe Van Schoonhoven (1838–1923).
He was a member of the New York State Assembly (Rensselaer Co.) in 1840, 1841 and 1845.
State Senator Jacobus Van Schoonhoven (1744–1814) was his grandfather; State Senator Guert Van Schoonhoven (1765–1847) was his uncle.
Senator John Kerry, was a great-great-granddaughter of Phoebe Van Schoonhoven (1838–1923).