During the English Civil War, he joined John Hampden's regiment as a captain and followed Oliver Cromwell into the New Model Army where he served as Colonel.
The money was recalled by subsequent vote, but it had already reached Oxford, and the soldiers forcibly took it and routed the escorting troops.
Ingoldsby himself was appointed one of the King's judges, which ended in his signing the death warrant, although there is no evidence that he was present at any of the previous court sessions.
Ingoldsby vigorously supported the new Protector, who was his own kinsman, but after the Rump Parliament removed Richard he threw in his lot with General George Monck and the move towards the restoration of the English monarchy.
Monck appointed him to command Colonel Rich's regiment (February 1660), and sent him to suppress John Lambert's intended rising (18 April 1660).
Lambert had escaped from the Tower where General George Monck had imprisoned him, and had tried to raise the supporters of the Good Old Cause in a last-ditch attempt to stop the English Restoration in 1660.
On 22 April Ingoldsby met Lambert's forces near Daventry, arrested him as he tried to flee, and brought him in triumph to London.
[3][4] He was not only spared the punishment which befell the rest of the regicides, but was created a Knight of the Bath at the coronation of Charles II on 20 April 1661.