At the age of nineteen, he joined a crew of privateers on Lyon, a frigate owned by Sydenham Teast.
Thereafter, King formed a relationship with Teast, and when Teast was looking for a crew to carry iron rods, rum, and clothes to skim the coast of West Africa in exchange for palm oil, King became involved in the proposed venture.
[1] After embarking on a few voyages to Africa, King bought African Queen and obtained a marquee to engage in profiteering against French interests when war was renewed between France and England.
His ships stocked goods from East India including, Calicoes, linen, cloth, gunpowder, beef, wine and sugar.
[1] By 1797, Thomas interest shifted to other places, he formed a venture along with his wife's family and other syndicates trading under the names J.