Poet. Born at Rosebank House near Roslin (Midlothian), the son of an impoverished army officer, at the age of fourteen MacNeill went to Glasgow then to relations in Bristol, as a counting-house clerk. He was sent to the West Indies, serving as manager of a plantation and then as a secretary on board a navy flagship (1780-86) before returning to Scotland. He was based in Stirling for a time but settled in Edinburgh c.1796, becoming a friend of novelist Elizabeth Hamilton (1758 - 1816).
MacNeill wrote various political pamphlets, including one in the defence of slavery, two novels, including The Memoirs of Charles Macpherson, based on his own adventures, together with several poems and songs. He also served as editor of the Scots Magazine. His poems include The Harp, a Legendary Tale (1789), Scotland's Skaith, or the History of Will and Jean (1795), a caution against the evils of whisky, and The Carse of Forth. He is perhaps best remembered for his songs, such as My Boy Tammy, I Loved ne'er a Lassie but Ane, Mary of Castlecary and The Plaid amang the Hether.
He died in Edinburgh.