Calvagh had positioned his branch of the O'Donnell dynasty, settled at Lifford, as friendlier to Crown interests than that of Hugh mac Manus, who had rendered himself suspicious by his alliance with the rebellious Shane O'Neill.
[4] Conn attempted to follow much the same policy as his father, being described by the Lord Deputy Thomas Radclyffe as "the likelyest plante that ever sprange in Ulster to graffe a good subject on.
"[5] The earliest mention of Conn is in 1557 when he participated in a daring night time raid at Balleeghan, Co. Donegal which halted a campaign undertaken by Shane O'Neill and Hugh mac Manus O'Donnell to undermine the leadership of Calvagh.
[6] In 1561, Calvagh was betrayed by a cabal of his subjects and captured by Shane O'Neill,[7][8] after which Conn assumed effective leadership of the Lifford faction of the O'Donnell dynasty.
[18][5] The confusion may arise from Shane's aggressive behaviour towards the O'Donnells and a reference to Conn as "cousin", interpreted wrongly in the broader Elizabethan sense of "relative", to Turlough Luineach.