He was the surviving son of Sir John Harington (later created Baron Harington of Exton in 1603) and his wife, Anne Keilway, daughter of Robert Keilway, Surveyor of the Court of Wards and Liveries, and was born at Combe Abbey, near Coventry, Warwickshire, in April 1592.

Friend and companion of Henry Frederick, Prince of Wales, on 5 January 1604 he was created, along with The Duke of York and others, a Knight of the Bath.

After seven weeks in the Low Countries, where he visited the universities, courts of three princes, and military fortifications, Harington went to Italy in 1608.

[4] Harington wrote from Venice (28 May 1609) announcing his intention of returning through France to spend the rest of his life with his royal friend.

[3] On 18 February he had sold the lordship of Exton to Sir Baptist Hicks,[6] and by his will, made at the same time, left the overplus of the estates, after the creditors had been paid (according to his mother the debts amounted to £40,000), to his two sisters, two-thirds to Lucy, Countess of Bedford, and one-third to Frances, Lady Chichester (d. 1615), whose kneeling effigy exists in Pilton Church in Devon, first wife of Sir Robert Chichester (1578–1627) of Raleigh.

His funeral sermon was preached by Richard Stock, pastor of All Hallows, Bread Street, and published as "The Church's Lament for the Loss of the Godly" (London, 1614), with a small woodprint portrait.