At the height of the civil war during Stephen's reign, and shortly after Chesney's consecration, the bishop acted as a guarantor for the treaty between Ranulf de Gernon, the Earl of Chester, and Robert de Beaumont, the Earl of Leicester, drawn up to limit the fighting between the two earls during the civil war. Chesney was present at the legatine council held by Theobald in March 1151, and was one of the judges, along with Theobald and Hilary of Chichester, the Bishop of Chichester, in a dispute between the monks of Belvoir Priory and a secular clerk over the right of the clerk to a church. Chesney appointed the future Archbishop of Canterbury, Thomas Becket, to a prebend in his cathedral chapter during the latter part of Stephen's reign.