Gildart was partner to his father-in-law, Sir Thomas Johnson, in the shipping, tobacco and rock salt business. By 1717 they were both deeply in debt to the Crown in respect of unpaid duty on tobacco. After Johnson left Liverpool in 1723 Gildart acted as his agent, taking over payments of the interest on his debts. In August 1723 the commissioners of the customs reported that Gildart
has hitherto made due payment of Sir Thos. Johnson’s bonds due to the Crown. But on 6 Sept. next another payment is due ... We have called on Mr. Gildart, but he hath not given another security in the room of Mr. Thos. Ball [Johnson’s brother-in-law] lately deceased. Neither has Gildart complied with the condition of his bond to pay £1,000 at last midsummer but says he hath met with disappointment and will certainly pay it at Michaelmas next.
During the following months the collector of the customs at Liverpool reported that Gildart had not paid ‘£300 due on account of Johnson’s hands on 6 September, nor on his own for £1,000’.
In 1734 Gildart stood for Liverpool, jointly with Thomas Brereton, against Thomas Bootle, who described him as ‘a merchant in the town, he is deeply engaged in custom-house bonds to the Crown and who must be in the same measures as [Brereton] and they too are making interest together upon the ministerial foot.’
a very little fellow ... I believe a merchant and attached to the Minister rather than Pelham, and his dealings in trade will keep him always under the lash of the Customs.
By this time he had become one of the leading Liverpool slave traders, sending ships to the Gold Coast to barter tobacco for slaves for the West Indies.
Gildart retired from Parliament in 1754. He obtained a grant of arms from the College of Arms in 1759. His portrait was painted by Joseph Wright of Derby in 1766.
