Lemuel Cushing Jr. was born on February 18, 1842, in Chatham, Argenteuil, Quebec.

He was a Canadian lawyer and politician. He studied law at McGill University and in 1865, he was admitted to the bar of the Province of Quebec. In politics, he was a Liberal and he represented the County of Argenteuil, Quebec, in the Dominion Parliaments. He took a keen interest in all athletic sports. He was President of the Montreal Lacrosse Club and one of the original members of the Montreal Amateur Athletic Association. He also took an active part in church and religious work, particularly of the Young Men's Christian Association of which he was at one time, President. He published the first Genealogy of the Cushing Family in 1877.

In 1869, he married Ellen Myra MacDougall (1849–1931). He died on March 1, 1881, in Montreal, Quebec.