H.W. Johnston was a collector and previous owner of the Johnston Collection of colonial Australasian stamps.
According to researcher Adam Fish of the Prahran Philatelic Society, Johnston was one of the founding members of the Prahran Philatelic Society in May 1905. He was Member No 1. He had a leather goods shop in Prahran. He died around 1928, but his bequest to the National Gallery of Victoria (NGV) did not come through until 1933 because of the time taken to research a suitable storage method. The Mitchell Library in Sydney was the model for the storage of the collection. Johnston's sons were Robert H. Johnston and D.S. Johnston.