[1] He was born in or before 1488 at the royal manor house at Brigstock, Northamptonshire, the 2nd son of Thomas Montagu (d. 1517) of Hemington, and Agnes Dudley, daughter of William Dudley of Clopton, and Christiana Darrell.

[1][6] He was a member of the Privy Council of Henry VIII, who appointed him one of sixteen executors of his last will, and governor to his son Edward.

[1] During the crisis of 1553 when Edward VI wished to alter the succession in favour of Lady Jane Grey, Montagu protested at the illegality of the proceedings.

[1] However, when the Duke of Northumberland called him a traitor and threatened him with physical violence, he withdrew his protest.

[9] Montagu married three times:[1] He died at Boughton on 10 February 1557 and was buried on 5 March with much pomp (including a "hearse of wax") in the church of St Mary, Weekley, where there is an altar tomb with his full-length effigy in robes and collar of SS and the motto "Pour unge pleasoir mille dolours" ("For every pleasure, a thousand sorrows").