Callaghan’s father was a successful merchant and shipowner of Cork, who in 1813 invested in an estate of 2,000 acres in Limerick. On 5 and 6 Apr. 1813, Gerard Callaghan gave evidence on the Irish corn trade to the select committee of the House. His father was a Roman Catholic, but he must have formally renounced the faith as he came in for Lord Roden’s borough of Dundalk in 1818, as a supporter of government and of Catholic relief. The chief secretary wrote him off as the ‘Papist of Cork’.
After the debate on the resumption of cash payments, 2 Feb. 1819, Callaghan returned home, so he informed Canning two days later, ‘so little instructed on the general bearings of that great question, that I determined, in preference to delivering my sentiments at length upon so dry a subject in the House, to address them to you in the form of a letter’. This was Callaghan’s first and not his only appearance in print upon a public subject. In it, he came out in favour of resumption and advised against further delay.
Callaghan appeared in the government majority on the case of Windham Quin, 29 Mar. 1819, but voted for Catholic relief, 3 May, and spoke and voted in the minority for the repeal of the Irish window tax, 5 May. He took part in the debate on the sinking fund, 13 May, calling for a ‘real and effective’, not a ‘nominal’ fund, and objecting to Grenfell’s motion. On 20 May his question about a newspaper report of the impending resumption of cash payments was ruled improper. On 8 June he supported the budget proposals in so far as they promoted a healthy sinking fund. He was in the minority on 14 June on the resumption of cash payments and possibly again on 18 June on the excise duties bill.
When in 1820 Callaghan stood for Cork city, Charles Arbuthnot at the Treasury advised the government against supporting him: ‘He is a friend but not very reputable, being a great stock jobber and always putting questions to Mr Vansittart’.