 Jacob made his senior championship debut in a 5-10 to 3-11 Leinster semi-final defeat by Offaly on 29 June 1969.Wexford regrouped in 1970, however, Jacob remained on the bench for their 4–16 to 3–14 defeat of old rivals Kilkenny in the Leinster final.Wexford subsequently faced Cork in the All-Ireland decider on 6 September 1970 and Jacob was back on the starting fifteen.