[1] Arriving just in time for the Indian Rebellion of 1857, MacGregor fought in a number of actions, including at Lucknow and was wounded twice.

[1] MacGregor earned successive promotions whilst serving variously in campaigns in China, the Bhutan War (where he became the deputy assistant Quartermaster General) and Abyssinia including at the Battle of Magdala.

In the Second Afghan War MacGregor served as Quartermaster General on the Khyber communication lines and commanded the 3rd Brigade of the Kabul-Kandahar field force at the Battle of Kandahar.

[2] After the Second Afghan War, training of men in intelligence gathering became the responsibility of the Quartermaster General and MacGregor served in this role for the East Indies until 1885.

"[4] The Institution awards the MacGregor Medal, founded in his memory, in recognition of valuable contributions to military intelligence that are of defensive importance to India.