The son of an actuary, and the fourth of four brothers, Jecks worked in the computer industry before becoming a novelist full-time in 1994 after he was fired from his last position.
Jecks has written a series of novels featuring Sir Baldwin Furnshill, a former Knight Templar, and his friend Simon Puttock, Bailiff of Lydford Castle.
He founded The Medieval Murderers, a speaking and entertainment group of historical writers including Bernard Knight, Ian Morson, Susanna Gregory, Phillip Gooden and CJ Sansom.
Jecks speaks at literary festivals and historical meetings, at which he talks with Ian Mortimer, the historian, as well as Medieval Murderers.
He also has a modern spy thriller published with Kindle, Act of Vengeance, and two short story collections: No One Can Hear You Scream and For The Love of Old Bones.