 He was appointed Sheriff of Warwickshire for 1582 and was knighted in 1584 by Sir Henry Sidney at Sir Thomas Henneage's house in London.Harington was a Knight of the Shire (MP) for Warwickshire in 1586, when he accompanied Mary, Queen of Scots through Warwickshire on her way to Fotheringhay in Northamptonshire.He was again MP for Rutland in 1593 and 1601 and was made Deputy Lieutenant of Rutland and Warwickshire during the 1590s.