He was executed for treason on 19 June 1535 for his refusal to accept Henry VIII's assumption of supremacy over the Church in England.

Sebastian Newdigate, born 7 September 1500 at Harefield, Middlesex, was the seventh of the fourteen children[1] of John Newdigate (d. 15 August 1528), esquire, Sergeant-at-law in 1510 and King's Serjeant in 1520, and Amphyllis Neville (d. 1544), daughter and heiress of John Neville of Rolleston, Nottinghamshire, "a kinsman of the Earls of Westmorland".

[6] In 1534 Henry VIII required his subjects to take the Oath of Succession recognizing Anne Boleyn as his lawful wife.

[16] Newdigate and two other monks, Humphrey Middlemore and William Exmew,[13] were arrested on 25 May 1535 for denying the King's supremacy, and imprisoned in the Marshalsea, where they were kept for fourteen days bound to pillars, standing upright, with iron rings round their necks, hands, and feet.

Along with the other members of his Order who suffered martyrdom at this time, Newdigate was beatified by Pope Leo XIII on 9 December 1886.