He took Holy Orders in 1629, and in 1633 in preaching before the court, standing in for Accepted Frewen, he won the approval of Robert Sidney, 2nd Earl of Leicester, and was presented with the living of Penshurst in Kent.
Soon after the meeting of the Long parliament, the committee for depriving scandalous ministers summoned Hammond, but he declined to leave Penshurst.
One of Charles I's last acts at Carisbrooke Castle was to entrust to Sir Thomas Herbert a copy of the book, to give to his son Henry Stuart, Duke of Gloucester.
[7] Hammond was chaplain to the royal commissioners at the Treaty of Uxbridge (30 January 1645), where he disputed with Richard Vines, one of the parliamentary envoys.
He returned to Oxford, and about 17 March 1645 Charles I bestowed upon him a canonry at Christ Church; the university chose him to be public orator at the same time, and he was made one of the royal chaplains.
About a fortnight later Hammond and Gilbert Sheldon, another royal chaplain, in company with James Stewart, 1st Duke of Richmond, joined the king.
Charles I, thinking he might trust his chaplain's nephew, escaped towards the Isle of Wight (12 November 1647), and was placed by the governor in Carisbrooke Castle, where Sheldon and Hammond again joined him.
He was soon summoned before the visitors at Merton College, and refused to submit to their authority, and was deprived and imprisoned, together with Sheldon, by an order of Parliament.
Colonel Evelyn, the puritan governor of Wallingford Castle, to whom Parliament sent an order for the custody of Sheldon and Hammond, declined to act as their gaoler, and said that he would only receive them as friends.
In August 1651 he attended Sir John Pakington, 2nd Baronet to the royal camp at Worcester, and had an interview with King Charles II.
In 1655 an ordinance was issued forbidding the ejected clergy to act as schoolmasters or private chaplains, or perform any clerical functions, thus depriving them of all means of subsistence.
Hammond died of an attack of stone on 25 April 1660, the day that Parliament voted that the king should be brought back; had he lived he would have been made bishop of Worcester.
Hammond was a pioneer Anglican theologian, much influenced by Richard Hooker and Lancelot Andrewes, but also by Arminianism in the form it took in Hugo Grotius, whom he defended in his writings.
[9][10] His defence and celebration of episcopacy as traditional was then followed by many English high church theologians: Miles Barne, Henry Dodwell, Fell, Peter Heylyn, Benjamin Lany, Thomas Long, Simon Lowth, John Pearson, Herbert Thorndike, and Francis Turner.