Edward Stanley, eldest son of the 14th Earl of Derby, was born on the 21st July 1826. He was educated at Rugby School and Trinity College, Cambridge. In 1848 Stanley went in a tour of the West Indies, America and Canada. While he was away he was elected as the Conservative MP for King's Lynn. As a result of his visit to the West Indies, Edward Stanley published a pamphlet putting forward the planters' case.
In 1852 the Earl of Derby became Prime Minister. He appointed his son as under secretary for foreign affairs. Stanley lost this post when the Earl of Aberdeen became the new Prime Minister later on that year. When Lord Palmerston became Prime Minister of the new Liberal government in 1855 he offered Stanley the post of colonial secretary. However, his father, who was still leader of the Conservatives, advised him to remain on the opposition benches.
The Earl of Derby became Prime Minister again in February 1858. He appointed his son as Colonial Secretary, and on the resignation of Lord Ellenborough, he became President of the Board of Trade. He held the post until Lord Palmerston returned as Prime Minister in 1859.
In the early 1860s Stanley was on the liberal wing of the Conservative Party. He agreed with some aspects of parliamentary reform suggested by the government of Lord John Russell. The speech that he made on Russell's proposed parliamentary reform bill in 1866 was considered by some of his colleagues as the best one he made in the House of Commons.
In 1866 the Earl of Derby became Prime Minister for a third time. Once again Stanley joined the Cabinet, this time as Foreign Secretary. Benjamin Disraeli became the new leader of Hose of Commons. Disraeli pointed out that although attempts by Lord John Russell and William Gladstone to extend the franchise had failed, he believed that if they returned to power, they would certainly try again. Disraeli argued that the Conservatives were in danger of being seen as an anti-reform party. In 1867 Disraeli proposed a new Reform Act. Although some members of the Cabinet such as Lord Cranborne (later the Marquis of Salisbury) resigned in protest against this extension of democracy, the Earl of Derby and Edward Stanley supported the measure.
In the House of Commons, Disraeli's proposals were supported by William Gladstone and his followers and the measure was passed. The 1867 Reform Act gave the vote to every male adult householder living in a borough constituency. Male lodgers paying £10 for unfurnished rooms were also granted the vote. This gave the vote to about 1,500,000 men.
In 1868 Earl of Derby resigned and Benjamin Disraeli became the new Prime Minister. However, in the general election that followed, William Gladstone and the Liberals were returned to power with a majority of 170 and Stanley returned to the opposition benches. In 1869 Stanley's father died and he succeeded him as the 15th Earl of Derby.
Benjamin Disraeli became Prime Minister in February 1874 and the Earl of Derby became Foreign Secretary. Derby main objective during this period was to prevent war in the Balkans. This policy ended in failure when Russia invaded Turkey in April 1877. The Cabinet was divided on what Britain should do. Derby believed that Britain should keep out of the war and when Disraeli made the decision to support Turkey, he resigned from the government. Lord Derby also opposed the acquisition of Cyprus and the Afghan War in 1879.
Unable to support the Conservative government's foreign policy, the Earl of Derby decided in March 1880 to join the Liberals. This move surprised many people as Derby was considered to be the most likely person to replace Benjamin Disraeli as leader of the Conservatives and therefore the future Prime Minister. William Gladstone was glad to have Derby in his party and asked him to be leader of the Liberals in the House of Lords. When Gladstone became Prime Minister in 1882 he appointed Derby as his Colonial Secretary. He held the post until the Marquis of Salisbury replaced Gladstone as Prime Minister in 1885.
The Earl of Derby disagreed with Gladstone's policy of Irish Home Rule and in 1886 joined the new Liberal Unionist Party. He led this party in the House of Lords until he retired in 1889.
Edward Stanley, 15th Earl of Derby, died on 21st April, 1893.