In that year he became lieutenant-colonel in the Earl of Morton's regiment, took part in the expedition to the isle of Rhé to relieve the Siege of La Rochelle, and was noticed as being one of the officers most favoured by the Duke of Buckingham.
He also received many other marks of the king's favour, including the grant in 1633 of a lucrative patent for making gold and silver money in the Tower.
Nevertheless, Balfour, "from the beginning of the Long parliament, according to the natural custom of his country, forgot all his obligations to the king, and made himself very gracious to those people whose glory it was to be thought enemies of the court".
[5] Perhaps religious motives had something to do with this change of parties, for Balfour was a devout Presbyterian[6] and a violent opponent of popery (as Roman Catholicism was called in England at the time), and had once beaten a priest for trying to convert his wife.
[7] Strafford was entrusted to Balfour's keeping, and though offered £20,000 and an advantageous match for his daughter, he refused to connive at the earl's escape, or to admit Captain Billingsley and his suspicious levies to the Tower.