Conrad Fulke Thomond O'Brien-ffrench was born in London, England, the second son of Henry Albert De Vreque O'Brien-ffrench, 1st Marquis de Castelthomond, and his wife Winifred née Thursby, heiress and daughter of Major James Legh Thursby, of Ormerod House Lancashire.

He and his elder brother Rollo (Rollo Adrien Vladimir Thursby Marie Altieri O'Brien-ffrench) spent their early childhood in Italy at Villa Torlonia (Frascati) in the Alban Hills, east of Rome, and then at Piazza dell'Indipendenza in Florence, where they received private tutoring in English, French and Italian.
Returning to England, Conrad joined Rollo at the Wick, a preparatory school at Hove in Sussex.
After Rollo left the Wick, Conrad completed his preparatory schooling at St. Aubyns School in Rottingdean, and then attended Bradley Court Agricultural College in the Forest of Dean, where he developed his lifelong interest in horsemanship, fox hunting and other country pursuits, and became a junior member of the Ledbury Hunt.
During these years his other siblings, Yvonne (Yvonne Castelthomond O'Brien-ffrench) and Alexis (Alexis Evelyn Henry O'Brien-ffrench), were born.
Conrad Fulke Thomond O'Brien-ffrench was born in London, England, the second son of Henry Albert De Vreque O'Brien-ffrench, 1st Marquis de Castelthomond, and his wife Winifred née Thursby, heiress and daughter of Major James Legh Thursby, of Ormerod House Lancashire.
He and his elder brother Rollo (Rollo Adrien Vladimir Thursby Marie Altieri O'Brien-ffrench) spent their early childhood in Italy at Villa Torlonia (Frascati) in the Alban Hills, east of Rome, and then at Piazza dell'Indipendenza in Florence, where they received private tutoring in English, French and Italian. Returning to England, Conrad joined Rollo at the Wick, a preparatory school at Hove in Sussex. After Rollo left the Wick, Conrad completed his preparatory schooling at St. Aubyns School in Rottingdean, and then attended Bradley Court Agricultural College in the Forest of Dean, where he developed his lifelong interest in horsemanship, fox hunting and other country pursuits, and became a junior member of the Ledbury Hunt. During these years his other siblings, Yvonne (Yvonne Castelthomond O'Brien-ffrench) and Alexis (Alexis Evelyn Henry O'Brien-ffrench), were born.
Conrad O'Brien-ffrench