The son of Delaval Loftus Astley, 18th Baron Hastings [d. 1872] and his wife, Hon. Frances Diana Manners Sutton [daughter of 1st Viscount Canterbury, d. 1874], George Manners succeeded his elder brother [Bernard Edward Delaval, 1855-1875, 19th Baron] as 20th Baron in 1875. He served as a Major in the Royal Army, and was a Justice of the Peace for Norfolk. On 17 April 1880, he married the Hon. Elizabeth Evelyn Harbord [d. 1957], daughter of the 5th Baron Suffield. They had three sons and three daughters; eldest son Albert Edward Delaval succeeded his father as the 21st Baron Hastings.