Harington probably spent part of his youth with his mother’s family, entering Shrewsbury school in 1564 with his cousin, Sir Philip Sidney†, whose father was then president of the Council in the Marches.
Harington served as sheriff of Rutland in 1593-4,
The Haringtons’ stock rose sharply on the accession of King James, with whom they claimed a very distant kinship: Harington was knighted by the king on the latter’s progress south in 1603, while his brother acquired a barony and was appointed governor to Princess Elizabeth.
Harington did relatively little with the seat his family laboured so hard to acquire. He and his brother-in-law Sir Edward Montagu were participants in a heated debate of 10 May 1604 over the report on the bill to ban the shooting of game birds. Later in the same day, Montagu’s brother Sir Henry* brought in a bill to indemnify the warden of the Fleet prison, who had refused to release the debtor Sir Thomas Shirley I* until he had been granted immunity from prosecution for the latter’s debts. Many Members wished to punish the warden by incarcerating him in the Tower, but Harington moved that he should be brought before the House once again, presumably to see whether a compromise could be arranged.
Harington may have helped promote some local measures within the House, as he was named to two committees for private bills concerning Northamptonshire estates, those of Dame Eleanor Cave (22 Jan. 1606) and Lord Spencer (7 Feb. 1606).
Outside the Commons, Harington was involved in extensive litigation on behalf of his relatives. He was involved in one dispute as trustee of the Kentish estates of his heavily indebted brother-in-law Sir Edward Wingfield†.
Harington undertook considerable expenditure in his final years: he paid the full £1,095 purchase price for one of the first baronetcies in 1611, and insisted in his will that the coat of arms on his funeral monument be altered to superimpose the red hand granted to all baronets, ‘which though I have not pride therein, so I do not disdain that badge His Majesty hath given me and my heirs male forever’.
Harington died on 3 Feb. 1614, a few months after his elder brothers Sir John and Sir Henry; his widow subsequently married Sir Henry Poole*. His nephew Sir John, 2nd Baron Harington, died within a few weeks, completing what the letter-writer John Chamberlain called ‘a fatal year for that family’.
