After graduating from Oxford with a BA in 1860, he entered
Parliament as
Conservative MP for
County Donegal, a constituency he represented from 1860 to 1880. He took over from his father as
Honorary Colonel of the
Prince of Wales's Own Donegal Militia on 22 September 1860, and retained the position until 1891 when his brother
Lord Claud Hamilton (who had been commandant of the regiment) took over. After serving as
High Sheriff of Tyrone for 1863, Viscount Hamilton re-entered university and emerged with an
M.A. in 1865 (he was created a
Companion of the Order of the Bath the same year). That year, he also embarked upon a diplomatic mission to
Denmark. He served as a
Lord of the Bedchamber to the
Prince of Wales from 1866 to 1885; in the latter year, he took over his father's position of
Lord Lieutenant of County Donegal, and inherited his father's peerage titles. He led the Lords' reply to the
Speech from the throne wearing the uniform of Lord Lieutenant of Donegal on 21 January 1886. He was chosen
Grand Master of the
Grand Lodge of Ireland in 1886, a post he held until his death. In 1887 he was appointed to the
Privy Council of Ireland. Abercorn held several positions after acceding to that title, including
Groom of the Stole to the Prince of Wales (1886–1891), and chairman of the
British South Africa Company. In early 1901 he was appointed by
King Edward to lead a special diplomatic mission to announce the King's accession to the governments of
Denmark,
Sweden and Norway,
Russia,
Germany and
Saxony. He was created a
Knight of the Garter. He died of
pneumonia at his house at 61
Green Street, Mayfair, at the age of 74. He is buried in the cemetery at
Baronscourt Parish Church, the traditional burial place of the Dukes of Abercorn and their families. In 1883, he held 76,500 acres in Tyrone and Donegal. He also held 2,100 acres in Scotland. ==Personal life==