He was second in command of John Pickering Regiment of Foot one of the original twelve foot regiments of the New Model Army and when John Pickering died on November 24 1645 he took command of the regiment and as was the custom then, the Regiment was known as John Hewson Regiment of Foot.
In 1647 Parliament passed an act against religious festivals, regarding them as "vain and superstitious observances" when the Mayor of Canterbury tried to enforce this act and stop Christmas there was a riot and John Hewson Regiment of Foot were sent to restore order which they did quickly.
In 1648 Hewson played a key role in Pride's Purge and the Army's occupation of London.
In January 1649 he signed the death warrant for Charles I marking him as a regicide.
In 1649 many in this regiment refused to fight in Ireland until the Leveller reform programme was implemented. 300 were cashiered out of the army without arrears of pay.
On the restoration of the monarchy he fled to Amsterdam where he died in 1662.
Richard Neville (later Lord Braybrooke) in a footnote from his 1825 edition of Samuel Pepys' diary:
John Hewson, who, from a low origin, became a colonel in the Parliament army, and sat in judgment on the King: he escaped hanging by flight, and died in 1662, at Amsterdam. A curious notice of Hewson occurs in Rugge’s "Diurnal," December 5th, 1659, which states that "he was a cobbler by trade, but a very stout man, and a very good commander; but in regard of his former employment, they [the city apprentices] threw at him old shoes, and slippers, and turniptops, and brick-bats, stones, and tiles. … At this time [January, 1659-60] there came forth, almost every day, jeering books: one was called 'Colonel Hewson's Confession; or, a Parley with Pluto,' about his going into London, and taking down the gates of Temple-Bar." He had but one eye, which did not escape the notice of his enemies.
Generations later after the occurrence of family bankruptcy the descendants of John Hewson migrated to Australia where they dwelled in the little country province of Benalla. The family has since exploded in population and spread out all over country New South Wales and Victoria including areas such as Kooringle, Uranquinty, Turvey Park and Melbourne.
Like their respected ancestor once did the husbands and family men of the Hewson family have immersed themselves in traditional trades such as teaching, building, teaching building, carpentry, piloting, model aircraft building, musical virtuosities and clergy duties. They are fine and reputable citizens respected in the community and much loved by all.