By the beginning of the 1840s, O'Connell had achieved an unparalleled role in the transatlantic anti-slavery movement, with even his detractors admitting the power of his words and his presence at any abolition gathering. The London Convention in 1840 had consolidated his position as an influential leader in the transatlantic struggle. It had also been the occasion on which he had promised publicly to publish an appeal, in the form of an address, to Irish-Americans, calling on them to oppose slavery. The timing was improprietous for O'Connell, coinciding with the relaunch of the repeal movement and his election as Mayor of Dublin, both of which combined with his usual parliamentary duties that required him to be in London. Nonetheless, at the beginning of 1842, the arrival of the ‘Address from the People of Ireland to Their Countrymen and Country-women in America’ was announced in Boston. The response was polarized: abolitionists were delighted with it, but Irish-Americans, who disliked being singled out on such a controversial issue, were embarrassed by it. The Address, rather than bolstering support for abolition, embroiled O'Connell in a further transatlantic controversy that was not entirely of his making.

The Address was an outcome of O'Connell's involvement in the London Convention. Despite becoming indelibly linked with his name, the Address had actually been written by two of the founders of the Hibernian Anti-Slavery Society, Richard Davis Webb and James Haughton.