He was articled to Andrew Heiton in 1866 and stayed with him until 1872.[2] He moved to Edinburgh, having secured a place in the office of David Bryce, then worked on Blair Castle for John Stewart-Murray, 7th Duke of Atholl.[2] After the death of Bryce, he moved to the offices of John Charles Hay.[2] He set up his own practice in 1883.[2]
Thomas Forbes Maclennan became his assistant in 1894 and eventually went into partnership with him in 1905.[2] Henry seems to have acted as practice manager from this point.[2]