Born near Jedburgh, Roxburghshire, Scotland, Laidlaw immigrated to the United States in 1852 with his parents, who settled in Franklinville, New York.

He attended the common schools and Ten Broeck Free Academy in Franklinville.

Laidlaw served two years in the United States Navy during the Civil War.

From 1871 to 1877, he was the federal assessor of internal revenue for New York's thirty-first collection district.

This article incorporates public domain material from the Biographical Directory of the United States Congress