[1] Medlycott began his career in Ireland as secretary and estate manager to James Butler, 2nd Duke of Ormonde.
In 1697, he was entrusted with a sensitive task of organizing opposition to a bill confirming the King's grant of James II's Irish estates.
[1] By 1705, Medlycott's brother, James, had increased his electoral influence at Milborne Port by acquiring additional burgages.
During the election campaign the post of deputy-steward of Westminster became available and he immediately wrote to Ormond, the high steward, reminding him that he had previously promised him this office.
Measures he was involved in included tightening the provisions of his Fires Act, establishing a workhouse in St. Martin-in-the-Fields, extending the powers of London's commissioners of sewers, regulating hackney coaches, incorporating peruke-makers into the Company of Barbers and Surgeons, raising the militia and limiting long periods of public mourning because of the disastrous effects on the silk trade.
He became a bencher of his Inn in 1712 and in July 1712 was appointed Commissioner of Revenue and Excise for Ireland by Robert Harley Lord Treasurer.
In July he petitioned Lord Oxford for repayment of the expenses he had incurred back in 1697 carrying out the Queen's commands with regard to her father's former Irish estates when she was princess.
He was reinstated as Commissioner for revenue and excise for Ireland in February 1728 and held it until October 1733 when his son-in-law was appointed his successor, on the ground that Medlycott was ‘obliged to remain in England as a Member of Parliament’.
His only recorded speech was made on 21 February 1733 against the clause in a bill relating to the restrictive import of sugar, molasses and rum into Ireland.