Congregational minister of a small chapel at Skene, near Aberdeen, Munro studied medicine at the University of Aberdeen but was not allowed to graduate as he was already a practising hydropathist. He wrote articles for the Glasgow Christian News, started and edited the Journal of Health which was then succeeded by the Aberdeen Water Cure Journal and Sanitary Reformer.

Munro started a hydro at Angusfield in 1850 but for some reason this proved unsatisfactory and he started a second one in its place a year later at Lochhead, where he stayed for about twelve years. He then moved to become Superintendent of the Cluny Hill Hydro at Forres, moving on to the Waverley Hydro at Melrose and, in 1873, back to Cluny Hill until 1881. After a year lecturing round Scotland, he took charge of Carpenter's hydro at Bishop's Teignton, Devon where he stayed till his death on 13 January 1883, aged 72.