Above the high-end boutiques and eateries of Albemarle St now stands a commemoration to the Kerryman, known as The Liberator, for his battle for the right of Catholics to sit in the British parliament.
The plaque marks his former home in the affluent Mayfair district.
Among those already honoured by the distinctive blue plates in the capital are John Lennon, Florence Nightingale, Charles Dickens, Karl Marx, and Jimi Hendrix.
Outside the house, Profor Martin Daunton of English Heritage, which issues the honours, said O’Connell was arguably the Mandela or Mahatma Gandhi of his age.
“His campaign for Catholic emancipation and his principled opposition to slavery was — and still is — admired around the world,” he said.
“We are delighted to honour this towering figure in the city which formed the backdrop for much of his career.”
O’Connell lived at 14 Albermarle St from February 1833 for up to six months, during a significant time for the groundbreaking 19th-century politician.
During that year’s general election, 39 of his supporters in the campaign against the Act of Union were elected to the House of Commons.
Laws to abolish slavery, in which O’Connell played a major role, were also enacted.
The plaque was unveiled at the house after O’Connell’s descendants proposed the idea to a panel of judges at English Heritage.
At the official unveiling, Geoffrey O’Connell, his great-great-grandson, said they were delighted to see the commemoration in a city which did much to shape his beliefs and ideals.
“The ‘prophet of a coming time’ was how the future British prime minister William Gladstone described O’Connell, and his peaceful struggle for universal rights for people of all races and creeds is as pertinent today as it was prescient then,” he said.
A four-storey terraced house dating from the 18th century, the property has been converted into apartments and a retail outlet, squeezed between designer shops.
The size of the house and its desirable location is a reflection of O’Connell’s stature at the time.
“I am anxious to make a good appearance in London for the sake of our girls,” he said to his wife, Mary.
O’Connell’s sons, Maurice, Morgan and John, and his son-in-law, Charles, also lived there.
Blue plaques are granted to historical figures who lived in London for a significant time and who are deemed eminent and exceptional in terms of their public and national recognition.
O’Connell regularly visited and lived in London after fleeing revolutionary France for the city in 1793 to study as a barrister.
Diaspora Minister Jimmy Deenihan and ambassador to Britain, Dan Mulhall, attended the unveiling.