The University of Toronto hasn't much to say about this John Galt. It gives his year of birth as 1779, his year of death as 1839, and his literary period as Romantic. One of the poems they give is in broad Scots, heavily footnoted, and a couple of others use Scots words here and there.Wikipedia says that he was born in Ayrshire, Scotland, and founded the city of Guelph in what is now Ontario. Wikipedia also gives "(novelist)" in apposition to his name, to distinguish him from the better known John Galt, the hero of Atlas Shrugged.
It seems improbable that Ayn Rand named her character after the literary John Galt. He was successful enough in business, but one of the poems that the University of Toronto offers is The Selfish, which begins
There is a death, an apathy profoundThat is not the Randian view of selfishness, as I understand it.
As that of those who in the churchyard lie,
Although the sepulchres be above ground,
Where rot these moral morts unconsciously.