Described in the Dictionary of National Biography as "a sensible, honourable and industrious public man", he was also serious, devout, chaste and had a one-track mind intent upon ecclesiastical 
legislation. Others regarded him a Victorian prig. In 1840 he matriculated from Oriel but remained there to receive tuition from a devout clergyman, which may explain his anti-Roman attitude. He was very much suited to his wife who was described as "a kind-hearted motherly sort of person---neither clever nor at all handsome". 
In 1857, as Lord Blandford, he pursued a Bill which would create new parishes and strengthen the Church of England and accordingly became known as the Blandford Act. In 1866 he was made Lord Steward of the Household and in 1867 Lord President of the Council. In 1874 he declined the Lord-Lieutenancy of Ireland due to financial pressure. The debts he had inherited from preceding Dukes of Marlborough forced him to sell the Sunderland Library, the famous gem collection, and the Limoges enamels. 
In 1876 his son-and-heir, the Marquess of Blandford, already married to Lady Alberta Hamilton, caused a scandal by an affaire with the Countess of Aylesford. The subsequent behaviour of his sons, the Marquess and Lord Randolph, caused social ostracism to the Marlborough family and this time the Duke gladly accepted the offer of becoming Lord-Lieutenant or Viceroy of Ireland. And there they remained until 1880. 
Marlborough took Lord Randolph with him. The latter was accompanied by his wife, Jennie, and their two-year-old son, Winston. When in 1878 the potato-crop failed in Ireland, the Duchess campaigned vigorously for a relief fund. 
When they returned to England and Blenheim, they found Blenheim in need of repair. The Duchess also devoted a great deal of her time to local charities. In June 1883 the Duke made his last appearance in the House of Lords to discuss the Bill on Marriage with a Desceased Wife's sister. The Duke was against allowing such marriages and, as he was in the majority, the Bill was not passed. A few days after his last speech, the Duke died of a sudden heart-attack. 
 

Source: Leo van de Pas