James Crosskill Mackintosh was an alderman (1878-1884) and mayor of Halifax (1884-1887)and an active bank accountant, Presbyterian, and businessman.

Mackintosh was born on 1 February 1839 in Halifax, Nova Scotia the son of John and Mary Catherine (Crosskill) Mackintosh. J. C. Mackintosh's father had emigrated from Inverness, Scotland. Although a native Nova Scotian, his mother was also of Scottish descent, and Mackintosh had a strict Presbyterian upbringing, attending St John's School and the Free Church Academy. In later life he would devote much of his spare time to religious pursuits. He became first president of the Halifax Young Men's Christian Association as well as a member of the board of management of the Presbyterian College. In addition, he was one of the founders in 1871 of Fort Massey Presbyterian Church, where he served as elder and clerk of session among other responsibilities. After leaving school at 16, Mackintosh had joined the Bank of Nova Scotia as a senior clerk and begun his apprenticeship as an accountant. Two years later, in 1857, he in fact became the bank's official accountant – the first person to hold such a title in the organization. Mackintosh remained at the bank for the next 18 years, during which time he developed a reputation for superior workmanship. He married Emma Isabel Grant on 15 April 1869. In 1873 Mackintosh left the Bank of Nova Scotia to set up his own business with Mather Byles Almon. Initially, the firm seemed to do well but the partners soon split up, Almon going into life insurance and Mackintosh continuing the brokerage and banking business under the title of J. C. Mackintosh and Company. From its head office in Halifax, the firm eventually set up branches in Fredericton, Saint John, New Glasgow, N.S., and Montreal. In 1878 he was elected to Halifax City Council, and he remained an alderman until 1884 when he was elected mayor serving until 1887. During his three annual terms as mayor he spearheaded major public works projects including a dry dock and a regular ferry service between Dartmouth and Halifax. He died in Halifax on 8 May 1924.