Edward was the eldest, but not the favourite, son of Sir Edward Unton (occasionally spelt Umpton), of Wadley House at Littleworth in Faringdon, Berkshire, by his wife, Anne, Countess of Warwick, the eldest daughter of the Lord Protector, Edward Seymour, Duke of Somerset, and widow of John Dudley, Earl of Warwick, the eldest son of his great rival, the Duke of Northumberland. 

He was educated at Oriel College, Oxford and was only twenty-five years of age at his father's death in 1582, when he inherited the family estates. He was not present at his father's funeral, due to his having left the country to follow in his footsteps on an Italian tour. However, the delights of Europe soon soured when, the following year, he was arrested by the Inquisition in Milan. His mother's brother-in-law and the Queen's favourite,  Robert Dudley, Earl of Leicester, was furious and threatened the Spanish Ambassador with English reprisals. However, it was left to Edward's younger brother, Henry, to travel to Lyons and negotiate a ransom. 10,000 crowns was agreed as long as Edward remained in Milan, but he was eventually allowed to return home in the Spring of 1584.

Poor Edward returned to Berkshire, something of a broken man, being both depressed and physically ill. Furthermore, his reputation was ruined as rumours spread that he had been recruited as a Catholic agent. He threw himself into local life and, though he did not execute the office of Sheriff, he was elected MP for Berkshire soon after his return and again the following year. However, he had to sell land in order to repay his brother Henry's considerable costs at his expense. He was lucky in that the Privy Council ordered that he should not be arrested for debt and commended the more considerate of his creditors. He tried to recoup some of his losses through being active in the colonization of Munster in Ireland, but he was recalled by the threat of the Spanish Amada Invasion in 1588. He was one of the captains of the Berkshire militia raised for the defence of the Kingdom , commanding two bodies of 200 men each, classed as trained and untrained, and each of which consisted of 100 men armed with calivers, eighty pikemen in corslets, and twenty bowmen.

The following year, he joined his neighbour and 5th cousin, Sir John Norreys, on his expedition to aid the restoration of Don Antonio to the Throne of Portugal. 'Colonel Umpton' is one of the officers mentioned in the narrative of the expedition, quoted by Stowe in his Chronicle and also by Camden in his Annales, as making a hot assault with their regiments upon the base town at the Groyne (Corunna) on 7th May. Mortally wounded or diseased, he managed to make it back to Plymouth where he died on 27th June 1589.

Edward married, firstly, Dorothy, the daughter of Sir Richard Knightley of Fawsley and Norton in Northamptonshire, by his first wife, Mary, the daughter of Richard Fermor of Easton Neston in the same county. She was the sister of Sir Valentine Knightley, who married Edward's sister, Anne. Sir Richard Knightley's second wife was Edward's aunt, Lady Elizabeth Seymour, the youngest sister of the Countess of Warwick. The Colonel's second wife, whom he married in 1579, was Katharine, the eldest daughter of Sir George Hastings (later Earl of Huntingdon) of Gopsal in Leicestershire. As with his first marriage, there was a previous family connection which led to this alliance. For Sir George's sister-in-law, Catherine, Countess of Huntingdon, was a daughter of John Dudley, Duke of Northumberland, and thus sister-in-law to the Countess of Warwick. Surviving her husband, Mrs Unton was married, secondly, to Sir Walter Chetwynd of Ingestre in Staffordshire by whom she had two sons. Colonel Edward Unton had no children and what was left of his estates were inherited by his brother, Henry.