Helenor and her husband were the keepers of Linlithgow Palace and from 1596, Princess Elizabeth, although she was believed by some to be unsuitable as a professed Catholic. She took some religious instruction from Patrick Simson, minister of Stirling, who was also involved in the religious conversion of Marie Stewart, Countess of Mar. The household at Linlithgow for the Princess included Margaret Stewart Lady Ochiltree, Alison Hay and Elizabeth Hay.
Princess Margaret was also entrusted to her, and on 13 March 1600 James VI of Scotland rewarded the Lord and Lady Livingston for educating both children, a service worth £10,000 for which he renewed and confirmed their lands at Callendar and Falkirk as baronies.
In 1606, the Earl and Helenor, described as "ane obstinat Papist", hosted six imprisoned ministers at Linlithgow including John Welsh, giving them better freedom than they had enjoyed at Blackness Castle. Patrick Simson and other allies were allowed to visit the prisoners.
Around the year 1615, she had to write to the king to avoid excommunication by the church of Scotland.
In 1629, John Wreittoun published a book describing her conversion; The confession and conversion of the right honorable, most illustrious, and elect lady, my Lady C. of L. However, some critics think the Confession was not her work.