His father was the youngest son of William Kerr, 6th Marquess of Lothian and his second wife, Lady Harriet Scott, daughter of the Duke of Buccleuch.

[3] He was promoted to captain on 1 January 1903,[4] and appointed Naval Attache in Italy, Austria, Turkey and Greece later the same year.

[2] In 1913, he succeeded Vice Admiral Lionel Grant Tufnell as head of the British Naval Mission to Greece, and as Commander-in-Chief of the Royal Hellenic Navy, a post he retained until 1915.

In 1914, while on leave from his duties as head of the Greek Navy, Kerr learned to fly, making him the first British flag officer to become a pilot.

[5] In May 1916 Kerr was appointed Commander-in-Chief of the British Adriatic Squadron[2] which meant that he was unavailable to the Committee which was investigating the Dardanelles failure.

To counter this threat, Kerr urged the creation of a bomber force consisting of no fewer than 2,000 aircraft which would be under the authority of an air ministry with its own executive powers.