Amherst came from a yeoman family resident in Kent since at least the fifteenth century.
It was probably the groom of the 1609 marriage, who soon after the nuptials succeeded as 3rd earl of Dorset, who nominated Amherst for Lewes in 1614. The latter was specifically appointed to only three committees, but made eight recorded speeches. He first spoke in the debate of 8 Apr. on whether the attorney-general, Sir Francis Bacon, was eligible to sit in the Commons, supporting moves to establish a committee to search for precedents and asserting that ‘divers new Parliament [men were] of the same mind’.
On 7 May Amherst spoke at the second reading of Sir John Sammes’ bill for revising statutes relating to the repair of highways. The text of this measure does not survive, but Sammes seems to have intended it, in part, to revive the provisions of the failed 1607 bill, which related specifically to Sussex, Surrey and Kent. Amherst called for consideration ‘how provision may be made by the committee for relief’ of the three counties, possibly fearing that the legislation would increase the burden of local taxation. He was not specifically named to the committee, but may have been entitled to attend as one of the Members of a county named in the measure.
Amherst supported three private bills connected with east Sussex. On 13 May he successfully moved for the commitment of the measure to enable Thomas Stolyon, a Wealden landowner, to sell lands to pay his debts, suggesting that Stolyon’s sons be called before the committee, presumably to testify to their support. He himself was subsequently named to the committee.
Amherst made one recorded contribution to the debates on impositions, on 16 May, but the sources give contradictory accounts of the speech. According to the Commons Journal, following Sir Dudley Digges’ call for anyone ‘unsatisfied’ about the illegality of the levy to speak, Amherst responded that he had doubts arising from the reports of the Tudor jurist Sir James Dyer†, and asked for Henry Finch to ‘satisfy’ him.
The following year Dorset appointed Amherst, together with Sir George Rivers* and Edward Lyndsey*, his trustees for selling lands to clear debts.
In the disturbed last days of the Parliament, following James’ angry response to the Commons’ petition concerning foreign policy, Amherst was among those who, on 7 Dec., opposed sending the Speaker with the House’s reply to the king.
Amherst was made a serjeant in 1623, at which ceremony Ralph Whitfield* presented his ring and the 3rd earl of Dorset, the 1st earl of Leicester (Robert Sidney†) and Sir Francis Cottington* acted as his patrons.
Amherst made his will on 8 Aug. 1630, praying for God ‘ever to defend me from my cruel, subtle and malicious enemy the devil and all his wicked spirits’. Through the earl of Dorset he had been drawn into the affairs of the London philanthropist Henry Smith, to whom he owed £1,000; but he declined to provide for the debt, claiming he had ‘painfully deserved’ so much ‘at his hands, and much more’ as one of Smith’s trustees. His brothers-in-law Sir Roger* and James Palmer* were named as overseers. He paid £28 for his knighthood composition on 13 July 1631 and died the following April. His burial was on 14th of that month at Lewes. None of his male descendants entered Parliament, but his granddaughter Dorothy married her cousin Jeffery Amherst, who sat for Bletchingley in 1689.
