Inglefield was commissioned into the 15th Regiment of Foot on 13 June 1874. He saw action at the Battle of Poplar Grove on 7 March 1900 and at the Battle of Driefontein in March 1900 during the Second Boer War for which he was appointed a Companion of the Distinguished Service Order. He became a staff officer with the 5th Division in November 1905 and was appointed a Companion of the Order of the Bath in the 1908 Birthday Honours.