[1] The son of Thomas Watts of Buntingford, Hertfordshire, he was the owner of the Margaret and John, one of the ships paid by the city of London in 1588 to sail against the Spanish armada.
In 1590 the same ship was one of a fleet of merchantmen coming home from the Mediterranean, which successfully fought and repelled the Spanish galleys near Cadiz, though Watts was not on board.
Throughout the war he equipped and financed privateers led by Michael Geare, William Lane and Christopher Newport, in highly lucrative joint stock expeditions.
His eldest son (grandson of the lord mayor), who also became Sir John Watts, served an apprenticeship in arms under his father.
He compounded for delinquency by paying a fine, and was discharged on 11 May 1649; however, he was forced to sell to Sir John Buck his manor of Mardocks in Ware.