[6][7][4][8][9] In the 1868 general election, he stood unsuccessfully as parliamentary candidate for Bury, Lancashire but was successfully returned as Member of Parliament for Bath in a by-election in May 1873, just before he was ennobled on the death of his father on 8 June and had to move to the House of Lords.

[7] By 1888, at the initiative of the Fifth Earl, building work was well underway at the south-eastern end of London's Sloane Street to rebuild Holy Trinity Church to the design of the leading Arts and Crafts architect John Dando Sedding.

Cadogan funded the entire initial operation, including the commissioning of numerous fittings for the new building by leading sculptors and designers including Henry Wilson (who assumed overall artistic control when Sedding died prematurely), Onslow Ford, Edward Burne-Jones, William Morris, Nelson Dawson and Henry Hugh Armstead.

Money was found for the installation of a great organ by James John Walker, which quickly became famous for its cathedral-like effect in the opulent acoustic of the building.

As Lord of the Manor of Chelsea, he held large estates there, much of which he dedicated to houses for the working class.