 Born the fourth son of John Kerr, 7th Marquess of Lothian and Lady Cecil Chetwynd Talbot.Kerr was educated at Radley College and joined the first-rate HMS "Prince Regent" as a naval cadet in August 1853.He saw action during the Crimean War serving in the first-rate HMS "Neptune" in March 1854 and then in the third-rate HMS "Cornwallis" in May 1855.