Simeon Pennewill spent his early years in Greenwood, Delaware, where his father was a prominent peach grower and active in the Republican Party. He completed his education at Wilmington Conference Academy and later inherited and managed the family's peach orchards. Pennewill's political career included two terms in the Delaware State Senate and a single term as Governor of Delaware, where he focused on party reunification and infrastructure development. As governor, he supported the sale of the Chesapeake and Delaware Canal to the federal government and facilitated the construction of a privately funded highway. Pennewill also made notable judicial appointments, including his brother as Chief Justice of Delaware.

Simeon Pennewill's political career reveals a strategic balancing act between progressive policy shifts and traditional governance. His support for the sale of the Chesapeake and Delaware Canal to federal oversight, while simultaneously enabling private highway construction, showcases an ideologically flexible approach. Pennewill's reduction of lashings for the whipping post, despite local support, highlights a nuanced stance on criminal justice reform. His appointment of his brother as Chief Justice underscores a deeply personal approach to governance, raising questions about the balance between familial loyalty and impartial justice.