Butler, James (a. 1488–1538), 10th lord of Dunboyne, was son of James Butler, 9th lord, and either Elinor, daughter of Sir Laurence Taaffe, or Catherine, daughter of Finghin MacCarthy Reagh. He became the head of the Dunboyne Butlers on his father's death (1508), and received livery of his estates before August 1509. Although he had lands in the Pale, Butler increasingly centred his activities on the liberty of Tipperary and his lands there. Much of his energies were taken up with the internal feuding among the minor Butler clans, and the efforts of Piers Butler (qv), self-proclaimed earl of Ormond, to reassert comital control from 1515. James Butler generally supported Piers's claims to the earldom and acted as his seneschal for the liberty (1515–17), but his allegiance was not constant. Between 1517 and 1519 Butler sided with Maurice Fitzgerald (qv), earl of Desmond, but returned to Piers's side by 1519, when he married Piers's daughter Joan. He again served as seneschal of the liberty (1520–23), and after this gave the earl £600 in sureties that he would support him.
Butler and Piers shared a common problem in the activities of the Butlers of Cahir. A state of almost open warfare reigned (1516–26) in Tipperary as Piers tried to assert his authority. James Butler was involved in several attempts to secure the peace with his cousins of Cahir; but when all efforts failed, he defeated them in pitched battle (1526). Relations between him and Piers worsened again in the late 1520s, perhaps over a royal grant of the manor of Lisronagh, and James returned to his support of the earl of Desmond (qv) against Piers and the king. He returned to obedience in June 1530, when he swore an oath of allegiance to the king at Waterford. His career serves to highlight the independent nature of most of the Anglo-Irish nobility in the first half of the sixteenth century. Butler supported Piers against the Butlers of Cahir; but when his own position was threatened, he was prepared to join Desmond's rebellion. During his rebellion, and probably before, Butler resorted to exacting coyne and livery from the people of Tipperary, despite several oaths that he would cease this practice. He was no different in this respect from Piers or the Butlers of Cahir. Throughout his life Butler played an important role in the reestablishment of comital authority within the Ormond lordship. His place as an important member of the second rank of Irish nobility was posthumously recognised by the crown in 1541, when his son was formally recognised as baron of Dunboyne.