Of his early professional employment there is no account, the year books and other reports entirely omitting his name; but that he had acquired considerable legal eminence may be concluded from his being placed in the office of solicitor-general on 8 July 1521.
He was succeeded in this post by Christopher Hales on 14 August 1525; and although he is not introduced into the list of attorneys general in Dugdale's Chronica Series, there is little doubt that he then followed Ralph Swillington in that office; as he is mentioned with the title in the will of Cicily Marchioness of Dorset, dated 6 May 1527; and as Christopher Hales was made attorney-general immediately after Lyster's elevation to the bench as chief baron of the Exchequer on 12 May 1529, apparently as his successor.
The remainder of his life he spent at his mansion in Southampton, which John Leland describes as being "very fair"; and dying on 14 March 1554, where he was buried in St. Michael's Church.
His monument represents him in scarlet robes (the colour of which has now disappeared), with a collar of S. S. round his breast, a judge's cap on his head, and a book in his hand.
His third wife was another Elizabeth and she is the one who was responsible for his memorial in St Michael's Church ' This article incorporates text from this source, which is in the public domain: Foss's Judges of England