Hardcastle Street was hamed after William Hardcastle Ward, a partner in the once famous house of Marcus Ward & Co.. Royal Ulster Works, Dublin Road, behind which it is situated. Origins of Belfast Street Names, John J Marshall.
Application of Messrs R.J. McConnell and Co. New streets on their property be named: 2 streets off Agnes Street - Glenfarne Street and Charleville Street; 2 streets off Old Park Road Gracebell Street and Mayfair Street, 4 streets off Dublin Road Ashbourne Street, Salisbury Street, Hartington Street, Hardcastle Street. Mr McConnell was requested to choose another name instead of Maryville Avenue as the word avenue is not suitable. Town Improvement Committee, 13th October 1886.