For a time, he worked as a blacksmith's apprentice in Flanders, though he maintained contact with the doings of the family through a confidential servant in the Seton household back in Scotland.
He seems, like all his family, to have been given study and researches of some kind, and to travel; and in 1708 Robert Calder, a minister of the Episcopal Church of Scotland, dedicated to him his edition of the Genuine Epistles of the St. Ignatius.
"He took with him three hundred men to the standard of James Stuart; but he appears to have carried with him a fiery and determined temper, the accompaniment, perhaps, of noble qualities, but a dangerous attribute in times of difficulty.
"[citation needed] The Seton family, as we have seen, had always been noted for their loyalty and their attachment to the old Church, and the last Earl, though he had renounced the Catholic faith, held firmly to the political creed of his ancestors.
His involvement in the rebellion was hastened by the treatment which he received from a body of the Lothian militia, who forcibly entered and rifled his mansion at Seton, as he alleged on his trial, 'through private pique and revenge.'
The Scotsmen proposed that they should take possession of Dumfries, Ayr, Glasgow, and other towns in the south and west of Scotland, and attack the Duke of Argyll, who lay at Stirling, in the flank and rear, while the Earl of Mar assailed his army in front.
The Earl of Winton disapproved so strongly of this plan that he left the army with a considerable part of his troop, and was marching northward when he was overtaken by a messenger from the insurgent council, who entreated him to return.
Robert Patten, who officiated as chaplain to the insurgents, and afterwards wrote a history of the rebellion, indeed states that the Earl 'was never afterwards called to any council of war, and was slighted in various ways, having often no quarters provided for him, and at other times very bad ones, not fit for a nobleman of his family; yet, being in for it, he resolved to go forward, and diverted himself with any company, telling many pleasant stories of his travels, and his living unknown and obscurely with a blacksmith in France, whom he served some years as a bellows-blower and under-servant, till he was acquainted with the death of his father, and that his tutor had given out that he was dead, upon which he resolved to return home, and when there met with a cold reception.
The young Earl of Derwentwater, an English Catholic involved in the same catastrophe, having pleaded "guilty" at his trial, (which, however, did not avail to save him) was induced by a priest who attended him on the scaffold, and hesitated giving him absolution, to retract the plea.
Sir Walter Scott refutes these insinuations: "But, if we judge from his conduct in the rebellion, Lord Winton appears to have displayed more sense and prudence than most of those engaged in that unfortunate affair.
"[citation needed] While lying in the Tower under sentence, a trusty servant managed to furnish him with a file or other small instrument (some say it was only a watch-spring),[dubious – discuss] with which he contrived to cut through the window bars in his cell and escaped.
"Thus terminated", says Sir Robert Douglas, "one of the principal houses in Great Britain, after subsisting for upwards of 600 years in east Lothian, and from thence spreading into several flourishing branches in Scotland."