Miller should not be confused with his contemporary Rev William Baird Millar/er, who belonged to the United Presbyterian Church of Victoria 1851–53, and never held a charge but engaged chiefly in teaching.
Miller laboured faithfully as a minister of the Free Presbyterian Church of Victoria, and was spoken of as "highly esteemed", "possessing good abilities", "amiable in character" and "commanding the love and respect of the community".
Miller had arrived in Melbourne the same day as Robert Lawson, the rector appointed by the Free Church of Scotland for the Academy planned by James Forbes and later known as Scotch College.
Of his own denomination, "he hoped they would have grace and courage to maintain their own integrity and consistency by refusing all further negotiations until this point (i.e. the legislative basis) should be conceded".
Miller and several other opponents of union on the proposed basis were expelled by the majority in April 1857, through an apparently illegal motion of 26 paragraphs by Dr. Cairns.
Miller returned to Britain around March 1865, where he served the English Presbyterian Church at St Helens, Lancashire for some years, before he retired to Callander in Scotland.