William Johnston established a robust foundation through his early education and legal studies, followed by a career marked by significant contributions to public service and legal reform. He served as prosecuting attorney and a member of the Ohio House of Representatives, where he championed causes such as the common-school law and the abolition of imprisonment for debt. Johnston's tenure as Surveyor General of the Northwest Territory and his judicial role in Cincinnati further demonstrated his commitment to public service. His later years were spent in Washington, D.C., where he practiced before the Court of Claims and the United States Supreme Court, and he played a key role in revising the statutes of the United States.

William Johnston's political identity is marked by an unexpected alignment of progressive social reforms with conservative economic policies. His advocacy for the abolition of imprisonment for debt, except in cases of fraud, juxtaposes his otherwise traditional fiscal stance. Johnston's powerful oratory on education, earning him the nickname "Booby Johnson," reveals a commitment to public welfare that contrasts with his later judicial conservatism. His founding of the first temperance society in his county underscores a surprising alignment with social purity movements. Johnston's career reveals a complex interplay between progressive social policies and traditional economic conservatism.