Muir was born in Glasgow, Scotland, one of four brothers amongst whom was William Muir, and educated at the grammar school of Irvine, the University of Glasgow, and the East India Company College at Haileybury.
Muir was born in Glasgow, the son of William Muir, one of four brothers amongst whom was William Muir. He was educated at the grammar school of Irvine, the University of Glasgow, and the East India Company College at Haileybury.