Loftus is the younger son of Nicholas Loftus, 1st Viscount Loftus and Anne Ponsonby, daughter of William Ponsonby, 1st Viscount Duncannon. His elder brother is Nicholas Hume-Loftus, 1st Earl of Ely of the first creation.
Loftus serves as High Sheriff of Wexford in 1744 and between 1747 and 1768 represents Bannow in the Irish House of Commons. Subsequently he sits for Wexford County until 1769, when he succeeds his nephew Nicholas Hume-Loftus, 2nd Earl of Ely, as Viscount Loftus. He is created Earl of Ely (second creation) in 1771 and is appointed a Knight Founder of the Order of St. Patrick on March 11, 1783.
In 1745 Loftus marries Frances Monroe, daughter of Henry Monroe of Roe’s Hall, County Down. Frances is a leading figure in Dublin society who wields some political influence, and is a much stronger character than her rather ineffectual husband, whom she seems to dominate completely. She dies in 1774.
There is a portrait of the couple, with Lady Ely’s nieces, Dorothea (Dolly) and Frances Monroe, the daughters of her brother Henry Monroe of Roe’s Hall, by the celebrated Swiss painter Angelica Kauffman, who visits Ireland in 1771. Dolly Monroe is one of the greatest beauties of the age, whose admirers include Henry Grattan and Oliver Goldsmith. She marries the politician William Richardson, and dies without issue in 1793. Her sister Frances marries Henry Read.
Loftus marries secondly Anne Bonfoy, daughter of Captain Henry Bonfoy and Anne Eliot, and sister of Edward Craggs-Eliot, 1st Baron Eliot. He has no issue by either marriage and at his death on May 8, 1783 his estates passes to his nephew Charles Loftus, 1st Marquess of Ely, the son of his sister Elizabeth and Sir John Tottenham, 1st Baronet. His widow dies in 1821, having outlived her mother, who lives to be 97, by only five years.
(Pictured: Henry Loftus (1709-1783), 1st Earl of Ely, and his wife Frances Monroe (d.1821), Countess of Ely, circa 1775, source National Trust, Upton House)