Born in 1775, Rochfort was part of the seventeenth generation to descend from the original de Rochefort settlers and, as such, enjoyed an impressive pedigree in the Anglo-Irish élite. He was named after his great-grandfather, the Hon. Robert Rochfort, speaker of the Irish House of Commons, and his grandfather, John (close friend and legal executor of Dean Swift), had also sat in the Commons for 47 years. The primary influence on his burgeoning political and social awareness was undoubtedly his father, John Rochfort (1735–1812), upholder of Protestant interests across several counties and owner of a considerable estate at Clogrennane, two miles outside Carlow town. Ambitious and capable, John Rochfort enjoyed a position of power and leadership among the Carlow gentry as chief administrator of the ‘Test Oath’ to Catholics and because of his pursuit of local Whiteboys and others who dared to disrupt the status quo. One can only imagine the impact on five-year-old Robert Rochfort when his father celebrated British victories in the American War of Independence with rifle salutes and feasting for his own corps of Volunteers at Clogrennane Lodge in 1780. To Robert, his father epitomised an assertive and omnipotent Ascendancy.
Like many a younger son of the gentry, Robert graduated from Trinity College, Dublin, in 1796 in holy orders, and he achieved a prestigious, if not lucrative, posting in his appointment as one of the chaplains-in-ordinary of the lord lieutenant in Dublin Castle. Rochfort managed to secure the attentions of the man himself, to the extent that Lord Camden promised to provide an independent living for him in the church. This advancement was interrupted, to Rochfort’s fury, by the outbreak of rebellion in 1798 and Camden’s departure from the country in June of that year. Robert returned to Carlow in early 1798 incredulous that his social and political inferiors would have the gall to rock his boat. Here was an opportunity to emulate his father’s fierce loyalist reputation, and, armed with the fearlessness and impetuosity of youth, violence was to be his first resort.