As Tammany Hall leader, Varian presided over a critical period in Democratic history, which saw the defection, and return of the Locofoco faction, which was in existence from 1835 until 1840, and was the decisive factor in the 1837 mayoral election won by Whigs against the divided Democrats.

In 1839, Varian beat Clark by 1,067 votes despite blatant electoral misconduct.

During Varian's first term, the legislature passed a bill that mandated voter registration and made it a lot harder to commit electoral fraud.

They had nine children, seven of whom survived infancy: In 1845 Varian quit politics and retired to Peekskill, where he died in 1864.

The Valentine-Varian House (1758) is a historic farmhouse that still stands on what used to be the Varian dairy farm in the Bronx along the route from New York City to Boston.