In 1639, Willoughby raised The King's Life Guard of Foot, composed of four companies, for service in the First Bishops' War and was given a Captaincy in the regiment. The following year, he was appointed High Steward of the Honour of Bolingbroke and the Manor of Sutton. When the Long Parliament was convened on 3 November 1640, he was summoned to the House of Lords by a writ of acceleration as Baron Willoughby de Eresby. In October 1641, Lord Willoughby and four companions, including Endymion Porter, visited Scotland. Their sight-seeing was recorded in an anonymous poem, "A Scottish Journie".