Joshua Clayton was born on July 20, 1744, near Wyoming in Kent County, Delaware, the son of John Clayton and Eleanor Edinfield Clayton. He grew up in a rural colony of farms, small market towns, waterways, and close connections to Philadelphia. The Clayton family possessed enough means and standing to provide him with advanced education, but he did not inherit the great wealth of a major planter dynasty. Clayton studied medicine in Philadelphia under Dr. John Redman, one of the city’s leading physicians and a founder of its professional medical institutions. Eighteenth-century medical training combined apprenticeship, reading, observation, and direct practice. Clayton learned anatomy and contemporary theories of disease as well as the preparation of medicines, bedside conduct, and the business of maintaining a practice. Philadelphia exposed him to the most sophisticated scientific and intellectual community in British North America. After completing his training, he returned to Delaware and practiced medicine. He married Rachael McCleary, the adopted daughter of Richard Bassett, a wealthy lawyer and planter who later became a prominent Revolutionary and federal politician. The marriage brought Clayton into an influential family network and helped establish him within Delaware’s public elite. Clayton also acquired land and became involved in local affairs. A rural physician occupied a position of unusual trust because he entered households during illness, childbirth, injury, and death. His work connected him with residents across the county and developed the reputation later needed for office. During the Revolutionary War he served as a militia officer and physician, but his public career rested on preparation begun well beforehand. Before becoming governor and United States senator, Clayton had been formed by a Kent County farming community, professional apprenticeship in Philadelphia, the practical demands of country medicine, marriage, and property responsibility. His path illustrates how medical expertise could become a route into politics in the early republic, especially in a small state where professional reputation and family connections carried great weight.