[2][3] He inherited the estate of Eaton Hall in Cheshire and land in Mayfair and Belgravia, London, and spent much of his fortune in developing these properties.

Although he was an MP from the age of 22, and then a member of the House of Lords, his main interests were not in politics, but rather in his estates, in horse racing, and in country pursuits.

The following year, on 28 April 1852, Grosvenor married his first cousin, the 17-year-old[4] Lady Constance Sutherland-Leveson-Gower, the fourth daughter of the 2nd Duke of Sutherland.

Two years later, in June 1882, Grosvenor married Katherine Cavendish, third daughter of the 2nd Baron Chesham and Henrietta Frances Lascelles.

Grosvenor was elected as Whig MP for Chester in 1847 and continued to represent that constituency until, on the death of his father in 1869, he succeeded as 3rd Marquess of Westminster and entered the House of Lords.

This played a part in Gladstone's resignation, the election of the Conservative Derby government and Disraeli's Second Reform Act.

After inheriting the estate, one of his first acts was to commission a statue of his eponym, Norman Hugh Lupus, who had been the 1st Earl of Chester, from G. F. Watts, to stand in the forecourt of the hall.

[11] It is said that the hall's guests "were not greatly amused" by the carillon of 28 bells that played 28 tunes and sounded every quarter of the hour during the day and night.

Douglas' biographer, Edward Hubbard, estimated that the duke commissioned four churches and chapels, eight large houses, about 15 schools and institutions, about 50 farms (in whole or part), about 300 cottages, lodges, smithies and the like, two cheese factories, two inns, and about 12 commercial buildings (for most of which Douglas was the architect)—and these were just the buildings in the city of Chester and on the Eaton estate.

[12] He commissioned G. F. Bodley to rebuild St Mary's Church in his Cheshire estate village of Eccleston, which was completed in 1899, the year of his death.

He held his own opinions on architectural styles and decoration, favouring the Queen Anne style rather than the Italianate stucco preferred by his father; for red brick and terracotta; for stucco to be painted bright orange, and railings in chocolate or red; and for Oxford Street to be paved with wooden blocks.

In 1875, he established a racing stable at Eaton, eventually employing 30 grooms and boys, with two or three stallions and about 20 breeding mares.

Grosvenor took an interest in the country pursuits of deer stalking and shooting, both in the Scottish Highlands and on his Cheshire estate and added to the family's art collection.

[5] In 1899, the last year of his life, he supported the Seats for Shop Assistants Act (to reduce cruelty to women employees), stalked a stag in Scotland, shot 65 snipe in 1½ hours in Aldford on his Cheshire estate, and attended the wedding of one of his granddaughters, Constance Ashley-Cooper, Countess of Shaftesbury, in July.

He frequently suffered from bouts of bronchitis in the winters and was reported to be recovering, but on 20 December his condition took a grave turn.

The 1st Duke of Westminster had two cenotaphs erected in his honour, one in the Grosvenor Chapel of Eccleston Church and another in the south transept of Chester Cathedral.