He had four brothers and a sister:[1] According to Lowe, Hales may have spent some time at Oxford, but 'was largely a self-taught scholar of Greek, Latin, Hebrew, and the law'.

According to Bindoff, the records show that Hales 'bore the brunt of the work' at the Hanaper, and in addition assisted Sadler with his duties as Master of the Great Wardrobe.

[9] When King Edward VI came to the throne in 1547, Hales was appointed a Justice of the Peace for Middlesex and Warwickshire, and became a member of parliament for Preston, Lancashire.

He was released in 1550, and after enfeoffing his lands to his brother, Stephen, and to Sir Ralph Sadler, obtained licence on 2 February 1551 to leave England in the company of Sir Richard Morison, who was being sent as ambassador to Holy Roman Emperor Charles V. Hales lived in Germany with his brother, Christopher, principally at Frankfurt, until Queen Elizabeth I came to the throne.

Mary's granddaughter Lady Catherine Grey had secretly married Edward Seymour, and the Queen had had them both imprisoned.

John Hales had secretly made a book in the time of the last Parliament wherein he hath taken upon him to discuss no small matter, viz., the title to the Crown after the Queen’s Majesty, having confuted and rejected the line of the Scottish Queen, and made the line of the Lady Frances, mother to the Lady Catherine, only next and lawful.

Beside this, John Hales hath procured sentences and counsels of lawyers from beyond seas to be written in maintenance of the Earl of Hertford’s marriage.

[12] Hales was long thought to be the author of the anonymous tract The Discourse of the Common Weal of this Realm of England (1581), but it was subsequently shown to be by Thomas Smith.