Henry Wilmot was the only surviving son of Charles, 1st Viscount Wilmot. He represented Tamworth in the Long Parliament, but was expelled in 1641 for his part in an army plot against Parliament. At the outbreak of the Civil War he joined the King in Yorkshire, and later fought at Worcester, where he was wounded, Edgehill and Roundway Down, where he inflicted a crushing defeat on Sir William Waller. In April 1643 he was appointed Lieut.-General of Horse in the King's army, and later the same year was created Baron Wilmot. His passion for intrigue made him enemies and charges were brought against him, but owing to his popularity with his brother officers, who petitioned the King on his behalf, the cases were droppped and he was allowed to go into voluntary exile in France.

After the succession of Charles II, Wilmot became one of the King's chief advisers, fighting with him at the battle of Worcester and helping him to escape to France in 1651. On 13th December 1652 he was made Earl of Rochester, and during the following years was employed by Charles on many diplomatic missions. He died at Sluys on February 5th 1657 or 8, and was buried at Bruges; after the Restoration he was reinterred at Spelsbury, Oxfordshire.

He married twice: first Frances, daughter of Sir George Morton, on 21st August 1633, and second, Anne, widow of Sir Francis Henry Lee, in 1644.

He was the father of John, 2nd Earl of Rochester, the Restoration poet.