 O'Neill was a trader, a Professed Knight of the Knight of the Order of Christ, Lord of many Majorats and of the Farms Quinta dos Bonecos and Quinta da Saboaria, at the term of Setúbal, etc.He inherited from his father-in-law the "Casa Comercial Torlades", of which he became the Main Manager, and the Farm Quinta das Machadas, in the Parish of São Julião, term of Setúbal, of which he became Lord by purchase.On 25 May 1825 the Farm was visited by King John VI of Portugal, accompanied by the Infanta Isabel Maria of Portugal and the Infanta Maria da Assunção of Portugal, and by the Court, being received and hosted by its Proprietor, the mentioned Carlos O'Neill, for whom the mentioned farm had passed on to, by marriage, by which the Crest of the O'Neill Family was placed over the door of the western front, etc.