He served briefly in the Army as Ensign of foot in the Duke of Buckingham's regiment from 1672 and then joined the Royal Navy as a midshipman in the galley HMS Charles in October 1677 before being promoted to lieutenant in April 1678.

[2] Aylmer transferred to the command of the third-rate HMS Mary in December 1688 and was present at the French victory at the Battle of Bantry Bay in May 1689 at an early stage of the Nine Years' War.

[6] Aylmer transferred again, this time to the command of the second-rate HMS Royal Katherine in Spring 1690 and was present at the French victory at Battle of Beachy Head in July 1690.

[10] Following the death of Prince George (Queen Anne's consort), which brought Russell back to the Admiralty, Aylmer was promoted to Admiral of the Fleet and Commander-in-Chief of the Navy on 12 November 1709.

He lost his Dover seat at the 1710 British general election which produced a landslide victory for the Tory party in the wake of the prosecution of Henry Sacheverell which Aylmer had supported.

[1] In July 1710, when Aylmer met a French squadron and convoy, he was only able to capture one merchantman and the 56-gun Superbe: the new Harley Ministry used this failure as an excuse to remove him as Commander-in-Chief and did so in January 1711.

[2] Following the accession of George I in August 1714, which led to the appointment of the Townshend Ministry in September 1714, Russell was back at the Admiralty again and Aylmer was reappointed Commander-in-Chief on 5 November 1714.

[11] Alymer was also appointed Governor of Greenwich Hospital on the same date:[11] in this post he started to fund education for the sons of seamen from entry charges to the Painted Hall, pensioners' fines and proceeds from the sale of stores.