As a member of the high court of justice in 1649, he was the 13th of 59 Commissioners who signed the death warrant of King Charles I. Post-Restoration, he was exempted from the general pardon, barring him from holding public office.

Sir Charles Lucas entered it in January 1644 and endeavoured to set it on fire, and in April 1645 a party from Newark captured the fort at Trent-bridges.

[12] On 22 December 1648, Hutchinson signed the protest against the votes of the House of Commons accepting the concessions made by the king at the treaty of Newport, and consented to act as one of the judges at the trial of Charles I.

[13] According to his wife, he was nominated to the latter post very much against his will; "but, looking upon himself as called hereunto, durst not refuse it, as holding himself obliged by the covenant of God and the public trust of his country reposed in him".

[14] From 13 February 1649 to 1651 Hutchinson was a member of the first two Councils of State of the Commonwealth,[12] but he took no very active part in public affairs, and with the expulsion of the Long Parliament in 1653 moved back to his family seat at Owthorpe near Nottingham and lived in retirement until 1659 when he was made High Sheriff of Nottinghamshire.

[15] According to his wife Lucy Hutchinson, Cromwell attempted to persuade her husband to accept office, "and, finding him too constant to be wrought upon to serve his tyranny", would have arrested him had not death prevented the fulfilment of his purpose.

He took his seat again in that assembly when the army recalled it to power (May 1659), and when John Lambert expelled it (October 1659) and prepared to restore its authority by arms, he secretly raised men, and concerted with Francis Hacker and others to assist George Monck and Arthur Hesilrige against Lambert and his party,[17] In his place in parliament he opposed the intended oath abjuring the Stuarts, voted for the re-admission of the secluded members, and followed the lead of Monck and Cooper,[18] in the belief that they were in favour of a Commonwealth.

On the same day he was made incapable of bearing any office or place of public trust in the kingdom, but it was agreed that he should not be excepted from the Act of Indemnity either for life or estate.

[19] In his petitions he confessed himself "involved in so horrid a crime as merits no indulgence", but pleaded his early, real, and constant repentance, arising from "a thorough conviction" of his "former misled judgment and conscience", not from a regard for his own safety.

[20] Thanks to this submission, to the influence of his kinsmen, Lord Byron and Sir Allen Apsley, to the fact that he was not considered dangerous, and that he had to a certain extent forwarded the Restoration, Hutchinson escaped the fate of most of the other regicides.

During his confinement in the Tower of London, he was treated with great severity by the governor, Sir John Robinson, and threatened in return to publish an account of his malpractices and extortions.

[16] In the opinion of the historian C. H. Firth that Hutchinson's defence of Nottingham was a service of great value to the parliamentary cause, but his subsequent career in Parliament and the Council of State shows no sign of political ability.