He spent many years attempting to exercise his right to hold the office of Chief Baron of the Irish Exchequer, which was also claimed by his Irish-born rival, John Cornwalsh.
[1] Little appears to be known of his background, but Griffiths states that by 1440 he already had a long record of good service to the English Crown,[2] and Elrington Ball describes his social rank as a "gentleman".
[6] In justice to Cornwalsh, it must be said that he was professionally undoubtedly the better qualified of the two rivals, having studied law at the Inns of Court in the 1430s, whereas Gryffin, judging by the references to him in a memorandum of 1442, had no legal qualifications at all.
John Gough, who served as second Baron for some twenty-five years, and like Gryffin was praised for his "good service" to the Crown, might have been an acceptable compromise candidate, but this was evidently not considered.
[7] The following year Gryffin was accused of "diverse offences" [1] but he refused to give up the struggle to remain in office as Chief Baron: in 1449 he sat as a judge on a commission of oyer and terminer, which his enemies promptly declared illegal.