27 Oct 1854 Acting Assistant Surgeon.
10 Aug 1855 Assistant Surgeon 1st, or The Royal Regiment of Foot.
Served in the Crimea. Was present at the siege and capture of Sebastopol.
Malta 11 June 1856 Arrived from Turkey.
Malta 22 May 1857 Left for Gibraltar.
Malta 16 July 1857 In the Collegiate Church of St Paul's Valletta, by the Reverend George Lawless Chaplain to the Forces, Angus John Mackay, bachelor born at Cape Town, Cape of Good Hope, son of William MacDonald Mackay and of Maria his wife, Assistant Surgeon 2nd/1st Royal Regiment, married Annette Blackford Tudor, spinister born in Ballaghaderreen, County Mayo Ireland, daughter of Captain Tudor 69th Regiment and of Elizabeth Ellen his wife.
16 May 1862 Staff Assistant Surgeon.
31 Aug 1863 Cashiered by the sentence of a General Court Martial. On 17 November, the vacancy created by Mackay was filled by Assistant Surgeon Patrick Kilgour 79th Foot.