[1] Algernon was the eldest of five sons of Fulke Greville-Nugent, 1st Baron Greville and his wife Lady Rosa Nugent.

Patrick Greville-Nugent, of Clonyn Castle, the High Sheriff of Westmeath (who married Ermengarde Ogilvy.

His sister was Hon Mildred Charlotte Greville-Nugent, who married Alexis Huchet, Marquis de la Bedoyére.

[2] In 1859, he purchased a commission as cornet and sub-lieutenant in the 1st Regiment of Life Guards, rising to the rank of captain before he retired in 1868.

[5] Her parents were the politician James Graham, 4th Duke of Montrose and the racehorse owner, former Hon.