Burghersh took an active role (1316) in the unhappy contests of parties in Edward II's reign as an adherent of his uncle, whom in 1317 he accompanied in an expedition to Scotland.
In October 1321, when Leeds Castle, Kent—the gates of which had been shut against Queen Isabella by Lady Badlesmere – surrendered to Edward, who had with unwonted spirit raised a force of thirty thousand men to avenge the insult offered to his wife.
In the unsettled relations between England and France, which lasted through the greater part of Edward IlI's reign, the responsibility devolving on the holder of these offices, which implied the command of the chief channel of communication between the two countries, was of the highest moment, and it evidences the confidence reposed in Burghersh that he should have held them almost continuously during so important an epoch.
Rymer contains a series of royal orders issued to him in his capacity of constable of Dover relating to prohibitions or licenses to cross the sea when the peace of the country was threatened, and to make arrangements for the passage of the king and other distinguished persons.
He was also appointed Seneschal of Ponthieu, Constable of the Tower of London, and Lord Chamberlain of the Household, in which capacity his presence is often recorded at delivery the great seal.
As Keeper of the king's forest to the south of the Trent in 1341 he was commissioned to provide timber for the construction of engines of war and 'hourdes' or wooden stages for the defenders of castle walls.
He was frequently sent as may be seen in Rymer – often in company with Bishop William Bateman of Norwich – to treat with the pope at Avignon, with Philip of Valois with the counts of Brahant and Flanders, and other leading powers, on the traces and armistices so repeatedly made and broken, and to arrange the often promised but long deferred final peace between the two contending nations.
As characteristic of the age, it is curious to find that under an excess of religious zeal, Burghersh, before the breaking out of the war with France when the return was comparatively quiet, had laid aside his arms and assumed the cross.
Two years after Crecy we find him again taking part in the French wars, and despatched to Avignon to treat with the pope for a firm and lasting peace between the two countries.