Constable served under Thomas Radclyffe, 3rd Earl of Sussex, in the campaign after the Northern Rebellion of 1569. On 17 April 1570 he went into Scotland with Lord Hunsdon to Jedburgh, took Ferniehirst Castle, and burnt Hawick, Branxholme and Bedrule. On 27 April he joined the siege of Hume Castle. He was knighted by Sussex at Berwick on 11 May 1570, together with William Drury, Thomas Manners, and George Carey, who were captains in the army sent into Scotland on the following day to assist the Earl of Lennox in the Marian civil war at Glasgow.