King was born in Dublin, the only son of Henry Eagles, a Church of Ireland clergyman. Eagles had assumed the name of King in 1821 upon inheriting the estate of his maternal uncle, John King, whose family had dominated the representation of the close borough of Jamestown, county Leitrim, in the Irish parliament.
After graduating from Dublin University King returned to his native county, and was nominated as high sheriff for King’s County in 1849 and 1850, being appointed to the position in 1852.
King supported the Conservatives in the Commons, opposing the abolition of church rates, 7 Mar. 1866, and attended the party meeting to oppose the Liberal reform bill in March 1866, voting against its second reading, 27 Apr., and supporting subsequent Conservative amendments to the measure.
King’s home was once described as ‘a beautiful specimen of the life and residence of a genuine “old Irish country gentleman”’, yet he encountered violent resistance to the payment of his rents during the ‘land war’ of 1879-82, and was mooted as a Conservative candidate for King’s County in 1874 and 1880.
