The older son of John King, Bishop of London, and his wife Joan Freeman, he was baptised at Worminghall, Buckinghamshire, 16 January 1592. He was educated at Lord Williams's School, Westminster School and in 1608 became a student of Christ Church, Oxford. With his brother John King he matriculated 20 January 1609, and was admitted (19 June 1611 and 7 July 1614) to the degrees of bachelor and master of arts. On 24 January 1616 he was collated to the prebend of St. Pancras in St. Paul's Cathedral, receiving at the same time the office of penitentiary or confessor in the cathedral, together with the rectory and patronage of Chigwell, Essex. He was made archdeacon of Colchester on 10 April 1617, and soon afterwards received the sinecure rectory of Fulham, in addition to being appointed one of the royal chaplains. All these preferments he held until he was advanced to the episcopal bench. Late in 1617 he preached a sermon at Paul's Cross. About this time King married Anne, eldest daughter of Robert Berkeley, esq., and granddaughter of Sir Maurice Berkeley. There were four or five children of the marriage, but only two survived. His wife died about 1624, and was buried in St. Paul's Cathedral, aged just 23.
He was a close friend of John Donne, who made him one of his executors, and presented him with his sermons in manuscript, and notes from his reading on over 1400 authors. Other friends were Ben Jonson, George Sandys, Sir Henry Blount, and James Howell. His friendship with Izaak Walton began about 1634, and was lifelong.
After his father's death, on Good Friday 1621, a rumour circulated that he had died in communion with the church of Rome. This was the subject of a two pamphlets attributed to Richard Broughton and George Musket. King preached a sermon refuting this claim on 25 November 1621. He was made canon of Christ Church 3 March 1624, and his brother John was made canon in the following August. On 19 May 1625 they were admitted to the degrees of B.D. and D.D.
On 6 February 1639 he was made Dean of Rochester, and on 6 February 1642, the day after the House of Lords had passed the bill to deprive the bishops of their votes, he became Bishop of Chichester; he was also presented to the rectory of Petworth in Sussex. He was residing at his episcopal palace when Chichester surrendered to the parliament in 1643, and his library was seized. He was deprived of the rectory of Petworth, which was given by parliament to Francis Cheynell, and by a resolution of the House of Commons, 27 June 1643, his estates were ordered to be sequestrated. From 1643 to 1651 he lived in the house of his brother-in-law, Sir Richard Hobart of Langley, Buckinghamshire.
Shortly afterwards King retired to Ritchings, near Langley, the residence of Lady Anne Salter (supposed to be the sister of Brian Duppa, where other members of the King family and John Hales of Eton found refuge. In 1659 King was engaged in negotiations for supplying the vacant bishoprics, and was reinstated at the Restoration, returning to Chichester. On 20 May 1661 he preached at Whitehall, and on 24 April 1662 he delivered an impressive funeral sermon on Bishop Duppa at Westminster Abbey. King died at Chichester 30 September 1669, and was buried in Chichester Cathedral, where the widow of his son John erected a monument to his memory and that of her husband. His second son, Henry, died 21 February 1669; his eldest son, John, died 10 March 1671.
King wrote many elegies on royal persons and on his private friends, who included John Donne and Ben Jonson. A selection from his Poems and Psalms was published in 1843.