On 20 March 1333, he was made a judge of the King's Bench, but was removed to the Common Pleas on 30 May following. On 30 November 1340, Edward III returned from the Low Countries and removed the chancellor, treasurer and other prominent officials, among them Shareshull, on a charge of maladministration. He was reinstated on 10 May 1342 and on 2 July 1344 he was made Chief Baron of the Exchequer. On 10 November 1345 he was moved back to the Common Pleas, with the title of second justice. He was appointed one of the guardians of the principality of Wales during the minority of the king's son. In 1346 he was styled “councillor and kinsman” of William de Montagu, Earl of Salisbury.
Chief judge
On 26 October 1350, he was advanced to the headship of the Court of King's Bench and presided over it until 5 July 1357. While holding that office he declared the causes of the meeting of five parliaments, from 25 to 29 Edward III. His functions seem to have more resembled those of a political and parliamentary official than those of a judge. In 1358 Shareshull, Edward de Montagu, and two others, executors of Elizabeth de Montagu, Countess of Salisbury, sued John Runaway in the Court of Common Pleas regarding a reasonable account of the time he was Elizabeth's bailiff in Worksop, Nottinghamshire and her receiver of money. In the last year of his chief-justiceship he was excommunicated by the Pope, for refusing to appear when summoned to answer for a sentence he had delivered against Thomas Lisle, the Bishop of Ely for harbouring a man who had slain a servant of Blanche, Lady Wake. In 1344 some sailors thought Shareshull stayed too long at dinner when he was holding assizes in that town. One of them mounted the bench and fined the judge for non-attendance. He took such offense at the joke that he induced the king to take away the assizes from the town and took the liberties of the corporation into his own hands for about a year.
Retirement
Though retired from the bench, he occupied confidential positions as late as 1361. He lived beyond 1364, in which year he granted his manor of Alurynton in Shropshire to Osney Priory, in addition to lands at Sandford in Oxfordshire, which he had given seven years before. He was a benefactor to the priories of Bruera, near Chester and Dudley. He left a son of the same name.
