In October 1764, he returned to England to deliver a load of masts from the Connecticut River, and to advise his successor as agent.

In 1765, he arrived in Boston from England charged with the commission of stamp agent for Connecticut, a position Benjamin Franklin had advised him to accept.

After the demonstrations against the obnoxious act in various parts of the colonies, Ingersoll, assured of the governor's protection, tried to reason the people of New Haven into forbearance.

His actions not satisfying the people of other sections of Connecticut, he resolved to place himself under the protection of the legislature in Hartford, in order to save his house from an attack.

Ingersoll said, "The cause is not worth dying for," and made a written declaration that his resignation was his own free act, without any equivocation.

With the onset of the Revolution, he incurred the displeasure of the Provincial Council of Pennsylvania, and in November 1777 was obliged to return to New Haven, where he died in 1781.

He lies buried in the Center Church Crypt, under a memorial tablet lavishly praising his "uncommon Genius" and "graceful and majestic Dignity," among other virtues.