John Malcom Forsyth worked at the bookshop of his uncle William Dymock from 1893. When Dymock died in 1900, he left his estate to his sister Marjory, and John Malcolm Forsyth became managing director and chairman of Dymock's Book Arcade. Under his management, Dymock's acquired the site of the Royal Hotel in George Street, Sydney, where the Dymock's Arcade remains today. Forsyth has been credited with developing the company into one of Australia's most successful booksellers. With G. B. Philip and T. E. G. Smith, Forsyth was involved in the founding of the Australian Booksellers Association.