[9] Viscount Thurles (courtesy title) predeceased his father, Walter Butler, 11th Earl of Ormond, and therefore never succeeded to the earldom.

[12][6] Hamilton's parents had married in 1635, despite earlier dates reported in error due to his father being often mistaken for his homonymous granduncle.

Lady Ormond with her children left for England in August 1652,[18] whereas John's mother moved to Paris where she lived in the Convent of the Feuillantines [fr].

[22] About that year Charles allegedly created Hamilton's father baronet of Donalong and Nenagh,[c] but the king if he really went that far, refused to go further because the family was Catholic.

[27] Hamilton now in his early thirties, became an officer in James II's Royal Irish Army, as did his older brothers Anthony and Richard.

Hamilton arrived on 5 February 1689 in France[31][32] and departed on the 17th with all the officers and soldiers (including his brother Anthony) from Saint-Germain.

[39] This was the first siege of the town during this war in which William had to concede defeat after a costly failed attack and when winter approached early.

During the campaign of 1691 in Ireland, Hamilton was involved in the Siege of Athlone, where he attempted to retake the city with two infantry brigades but failed.