After graduating as valedictorian in 1757, he studied briefly at Cambridge University before being ordained an Anglican clergyman by the Bishop of London and returning to the colonies.

That the scene of blood may be speedily closed; that order, harmony and peace may be effectually restored, and truth and justice, religion and piety, prevail and flourish amongst the people.

When the British occupied Philadelphia in September 1777, Duché was arrested by General William Howe and detained, underlining the seriousness of his actions.

In consequence, Duché fled to England, where he was appointed chaplain to the Lambeth orphan asylum, and soon made a reputation as an eloquent preacher.

His daughter, Elizabeth Sophia Duché (born on September 18, 1774, Philadelphia; died on December 11, 1808, Montréal), married Captain John Henry in 1799.