[1][2][3] He was the third and youngest son of Prince George, Duke of Cambridge, a member of the British royal family, by Sarah Fairbrother.

[4] Through his father, FitzGeorge was a male-line grandson of Prince Adolphus, Duke of Cambridge, and great-grandson of King George III.

[5] He attended the Royal Military College, Sandhurst and was gazetted in December 1864 as an ensign into the 37th (North Hampshire) Regiment of Foot.

[3] While FitzGeorge was stationed at Aldershot, his regiment was ordered to embark for service at the Cape of Good Hope following the outbreak of the First Boer War.

[17][18] He became extra aide-de-camp to Lieutenant-General Sir Archibald Alison, 2nd Baronet, who was in command of troops at Aldershot Garrison on 1 December 1883.

[3] While his father continued to reside officially at Gloucester House,[20][21] his mother lived at nearby 6 Queen Street, which FitzGeorge inherited, along with all of its furniture, following her death in 1890.

[2][3] As equerry to the Duke of Cambridge, FitzGeorge accompanied his father as an attendant to significant British royal engagements, including: the funeral of his grandmother, Augusta, Duchess of Cambridge, on 13 April 1889;[29] the wedding of his cousin Princess Mary of Teck and Prince George, Duke of York, at Chapel Royal, St James's Palace, on 6 July 1893;[30] the funeral of his aunt, Princess Mary Adelaide, Duchess of Teck, at St George's Chapel, Windsor Castle, on 3 November 1897;[31] and the funeral and funeral procession for his uncle Francis, Duke of Teck, at St George's Chapel, Windsor, on 27 January 1900.

[37] In 1911, FitzGeorge and his brother served on an honorary committee for the Ancient Art Exhibition at Earls Court in the summer of that year.

[39] FitzGeorge and Adolphus continued a longstanding family tradition of distributing gifts of blankets and flannels to the employees of the former Duke of Cambridge's Coombe estate at Christmas.

[45] In November 1913, the brothers were named as godparents (along with their cousin Queen Mary) to their great-nephew Victor FitzGeorge-Balfour, and attended his christening at Savoy Chapel.

[48] By 1933, FitzGeorge served as the president of the National Health League, an organization that claimed a membership of approximately 2,000 British physicians.

[49] The league was organised after ten years of planning, and in July 1933, it took issue publicly with the British Medical Association and with germ theory as the sole cause of disease.

[49] The National Health League contended that environmental factors also played a role in illness, emphasised the importance of preventive healthcare and accused the British medical establishment of operating for profit.

[49] At a meeting of health experts, FitzGeorge claimed that the British Army rejected 75 per cent of recruits for having preventable medical conditions.

[3] At 86, he would have been one of the longest-living members of the British royal family, had he been recognized with the title and style of a male-line descendant of George III.

[52][53] The first part of the funeral service was held at Chapel Royal, St James's Palace, with the permission of King George V.[52][53] King George and Queen Mary were represented by Edward Colebrooke, 1st Baron Colebrooke; Edward, Prince of Wales by his equerry Lieutenant Colonel Piers Legh; Prince Albert, Duke of York by Lieutenant Colonel Dermot McMorrough Kavanagh; and Prince Arthur, Duke of Connaught and Strathearn by Lieutenant Colonel Sir Malcolm Donald Murray.