Watson moved to New York City in 1786 and became a merchant at 44 Broad Street.

[1] In 1798, Watson was elected as a Federalist to the United States Senate to fill the vacancy caused by the resignation of John Sloss Hobart and served in the 5th and 6th United States Congress from December 11, 1798, to March 19, 1800, when he resigned to accept an appointment by President John Adams as Naval Officer of the Port of New York.

[1] Watson’s townhouse, located at 7 State Street in New York City still stands and is on the National Register of Historic Places.

[2] It was also the residence of Elizabeth Ann Seton, the first American Catholic Saint.

The home is currently occupied by the rectory of the Our Lady of the Holy Rosary Church and is part of the Seton Shrine.