Quinlan was born in 1909. He was the first editor-in-chief of the University of Chicago Law Review. He co-authored the Code of Fair Competition for the baking industry under President Franklin D. Roosevelt. As an attorney in Washington, D.C. for forty years, he represented small business associations before the U.S. Congress and the Executive Branch. He and his wife of 31 years raised three children. His second wife of 31 years, born in Ireland, was immersed with him in Irish affairs through a Maryland chapter of the Ancient Order of Hibernians. Quinlan was a devoted Catholic, a life-long Republican, a public servant, and a poet. He loved golf, hunting, and fishing. He was ahead of his time in advocating for racial justice. Due to his involvement in an accident which may have led to his second wife's death, he died a nearly broken man at age 91.