Bookseller and publisher at Ludgate Street (1758-1773) and on Fleet Street (1773-1790). In 1761 he married a Miss Chillingworth. He published the magazine The North Briton for Wilkes and Churchill until 1763. His publication of the magazine ceased with the printing of the notorious no. 45, for which he and Wilkes were arrested for accusing the King of lying. Kearsley was soon discharged, but Wilkes was forced to go into exile in France. Kearsley resumed trading and later specialised in engravings and copperplates, publishing the magazines Copperplate Magazine, or a monthly treasurer for the admirers of the imitative arts (1774-1778) and The Virtuosi's Museum (1778-1781)
After his death, his widow continued to run the publishing business before passing it on to their son, George (known as George Kearsley the Younger) in 1796. They also had a daughter, Catherine, who married the printer Thomas Davison (d. 1830) in 1799.
Boswell mentions in his journal of February 9, 1763 that he used to go to a pamphlet shop near the Temple Exchange Coffee-house to get The North Briton, but that he was now having it sent to him directly by Kearsley, the publisher.