Born on 14 November 1892, he was educated at Blundell's School and Bristol University. He interrupted his medical education when war broke out in 1914 to join the Gloucestershire Regiment as a combatant officer. He resumed his medical studies in 1917 and qualified the following year with the Conjoint diploma. Then he joined the RAMC and was drafted to Constantinople with the Army of Occupation. He completed his medical studies in 1922 and became surgical registrar at Bristol Royal Infirmary. Jackman took the FRCS Ed in 1924, and was appointed assistant surgeon to Bristol Royal Infirmary and to the Royal Hospital for Sick Children; he became surgeon to both these hospitals until his retirement in 1958. Jackman was an enthusiastic member of the Territorial Army, RAMC, between the first and second world wars. When war broke out in 1939 he served again in a field ambulance, in army hospitals, and in a troopship, and retired with the rank of honorary colonel. He was chairman of the Bristol Division of the BMA 1946-47, and president of the Bristol Medico-Chirurgical Society 1950-51. Jackman was endowed with humility, courtesy, and kindness. He lived at the Coppice, Twickenham Hill, near Clevedon, Somerset, and died on 6 March 1964 aged 71, survived by his wife and four daughters.