Born on 11 October 1856 at Buenos Aires, the second son of George Mackern, who was in business in the city, he was educated at the Blackheath Proprietary School and was admitted to Caius College, Cambridge in April 1878, having already qualified MRCS and LRCP from Guy's Hospital, where he was house surgeon. He was a scholar of the College from Michaelmas 1878 to Michaelmas 1881, and. Graduated BA after being placed in the third class of the Natural Sciences Tripos, Part I. He practised in Shooter's Hill Road, Blackheath, was for a time assistant physician to the Chelsea Hospital for Women, and was surgeon to the Royal Kent Dispensary, afterwards the Miller General Hospital, from 1893 till his resignation in 1907. He married in 1881 L Kidd, who survived him with one daughter. He died very suddenly at Silverwood, Newick, Sussex, on 31 January 1934.