He afterwards appeared openly in the MacGregor's country; and, notwithstanding his outlawry, married a daughter of Graham of Drunkie, a gentleman of some property.

His wife died a few years afterwards.
The insurrection of 1745 soon afterwards called the MacGregors to arms.
Robert MacGregor of Glencarnoch, generally regarded as the chief of the whole name, and grandfather of Sir John, whom the clan received in that character, raised a MacGregor regiment, with which he joined the standard of the Chevalier.

The race of Ciar Mhor, however, affecting independence, and commanded by Glengyle and his cousin James Roy MacGregor, did not join this kindred corps, but united themselves to the levies of the titular Duke of Perth, until William MacGregor Drummond of Bolhaldie, whom they regarded as head of their branch, of Clan Alpine, should come over from France.

To cement the union after the Highland fashion, James laid down the name of Campbell, and assumed that of Drummond, in compliment to Lord Perth.

He was also called James Roy, after his father, and James Mhor, or Big James, from his height.