Loftus was appointed by Lord Palmerston to the diplomatic service in 1837 as attaché at Berlin.[1] He was attaché at Stuttgart in 1844. He was secretary to Sir Stratford Canning in 1848, and after serving as secretary of legation at Stuttgart (1852), and Berlin (1853), was envoy at Vienna (1858), Berlin (1860) and Munich (1862).
Loftus married a distant cousin, Emma Maria Greville, daughter of Vice-Admiral Henry Francis Greville, in 1845. They had three sons and two surviving daughters. One of their sons would have succeeded George Loftus, 7th Marquess of Ely (1903–1969) as the 8th Marquess of Ely, but all three predeceased their cousin.[6]
Unnamed daughter (17 August 1846), stillborn at Baden-Baden[7]
Evelyn Ann Frances Loftus (4 December 1847 – 28 September 1861), died at Baden-Baden aged 13[8]
Henry John Loftus (8 November 1849 – 4 October 1924), married Sarah Josephine Leech, daughter of William Leech of Philadelphia
Capt. Augustus Petham Brooke Loftus (6 July 1851 – 25 March 1924), married in 1885 Ethel Adelaïde Labertouche, daughter of Peter Paul Labertouche; had one son:
Guy Alvo Greville Loftus (26 August 1899 – 7 August 1965), heir presumptive to the Marquessate of Ely from 1935 until his death[9]
Emma Anne Caroline Bloomfield Loftus (15 February 1855 – 21 August 1937); married first in 1873 Hon. Frederick Arthur Wellesley, son of Henry Wellesley, 1st Earl Cowley (divorced 1882); married second in 1903 Lebrecht von Köller [de][10]
Montagu Egerton Loftus (22 January 1860 – 27 November 1934), married Margaret Julia Agnes Fairfax Astell (died 1900), daughter of John Harvey Astell; and secondly in 1904 Colina Marion Hale Monro
Lady Augustus died in January 1902. Loftus survived her by two years and died in Surrey, England, in March 1904, aged 86.