He was born to Edward Smith-Stanley, 14th Earl of Derby, who led the Conservative Party from 1846 to 1868 and served as Prime Minister three times, and Emma Caroline Bootle-Wilbraham, daughter of Edward Bootle-Wilbraham, 1st Baron Skelmersdale, and was the older brother of Frederick Arthur Stanley, 16th Earl of Derby, for whom the NHL's Stanley Cup is named.

[2] In March 1848 he unsuccessfully contested the borough of Lancaster, and then made a long tour in the West Indies, Canada and the United States.

[4] From the outset of his career, he was known to be more politically sympathetic to the Liberals rather than the Conservatives, and in 1855 Lord Palmerston offered him the post of Secretary of State for the Colonies.

He was much tempted by the proposal, and hurried down to Knowsley to consult his father, who called out when he entered the room, "Halo, Stanley!

When the object of his sudden appearance had been explained, the Conservative chief received the courteous suggestion of the prime minister with anything but favour, and the offer was declined.

He compared his conduct in that great post to that of a man floating down a river and fending off from his vessel, as well as he could, the various obstacles it encountered.

[3] He enunciated the policy of Splendid isolation in 1866: He arranged the collective guarantee of the neutrality of Luxembourg in 1867, likely to be a theatre of war with the conflict between France and Prussia growing ever more likely.

[8] Derby acquiesced in Disraeli's purchase of the Suez Canal shares, a measure then considered dangerous by many people, but ultimately most successful.

By October 1879, it was clear enough that he had thrown in his lot with the Liberal Party, but it was not till March 1880 that he publicly announced this change of allegiance.

[11] Lord Derby married Lady Mary, daughter of George Sackville-West, 5th Earl De La Warr and widow of James Gascoyne-Cecil, 2nd Marquess of Salisbury, in 1870.