Clarendon says of him that 'he was of a lovely and winning presence, and genteel conversation.' He also accompanied the Duke of Buckingham to Holland on a diplomatic mission. On the first breaking out of an insurrection of the Scots, he was made General of the Horse, and though not in arms at the commencement of the Civil War, when evil days fell on the King, Lord Holland joined him with many other loyal noblemen, and on his being appointed General of the Royal army, numbers flocked to ask commissions from him. In 1648, after many fluctuations of fortune, he was pursued and taken prisoner near St. Neot's in Huntingdonshire, whence he was conveyed to Warwick House, and finally to the Tower, and a High Court of Justice was appointed to sit for the trial of the Earl of Holland, the Duke of Hamilton, and other Peers. He was in ill-health at the time, and when examined answered little, 'as a man who would rather receive his life from their favour than from the strength of his defence.' He was condemned, however, in spite of the influence of his brother, the Earl of Warwick, and the exertions of the Presbyterian party. There was not a large majority against him, but Cromwell, it would appear, disliked him extremely, and accordingly on the 9th of March 1649, Lord Holland suffered death immediately after the Duke of Hamilton.
Spent by long sickness, he addressed but few words to the people, recommending them with his last breath to uphold the King's government and the established religion.
He left four sons and five daughters. Robert, the eldest, succeeded to his father's honours, and likewise to the Earldom of Warwick on the death of his uncle in 1672.
