Gall, the son of a notary, was born at Linkhouse, near Dunbar, in December 1776.
Having attended the parish school of Haddington, he was apprenticed at the age of eleven to his maternal uncle, a carpenter, and builder.
He afterward became a printer's apprentice in Edinburgh, and there he gave his leisure to study.
He then became travelling clerk to a Mr. Ramsay, in whose employment he remained till his death, 10 May 1801.
His powers attracted considerable attention during his lifetime, and he enjoyed the friendship of Burns and Thomas Campbell.