Sylvester Pennoyer graduated from Harvard Law School and moved to Oregon in the mid-1850s. He began his career as a teacher and lawyer, later serving as Superintendent of Multnomah County schools. Pennoyer transitioned to the lumber industry and owned a Democratic-leaning newspaper. He was involved in a significant legal case that reached the U.S. Supreme Court, which defined legal jurisdiction for citizens residing in different states.

Sylvester Pennoyer's political career reveals an intriguing blend of regional protectionism and legal pragmatism. His advocacy for American labor over Chinese immigrants during his gubernatorial campaign highlights a protectionist stance, yet his involvement in the landmark legal case Pennoyer v. Neff, where he lost, demonstrates a willingness to engage with complex legal issues. This juxtaposition of ideological rigidity and legal engagement suggests a highly calculated approach to governance.