After John Rowan completed his coursework at Salem Academy in Bardstown, Kentucky, he was encouraged to study law. Heeding this advice, Rowan studied under Kentucky's leading lawyer George Nicholas. Nicholas was a personal friend of Thomas Jefferson with impressive abilities and an extensive understanding of law.
Upon completing his training with Nicholas, John married Captain John Lytle's daughter Ann Lytle in October of 1794. The couple was married at Ann's father's home "Elm Hill." Elm Hill was located near land which John Lytle later sold to Henry Clay for the construction of Ashland, the Clay family home. As a wedding gift, John Lytle gave John Rowan and Ann a large sum of money that was used to purchase the land east of Bardstown that eventually became the Federal Hill farm. The couple initially occupied a log house constructed on the land years before.
John and Ann began their family in 1798, having 9 children. The growing family necessitated the construction of a new and larger home. With the income produced through farming profits, land speculation, business transactions, and a promising personal career, John and Ann were financially able to build their new home that they named "Federal Hill" in honor of the Federal political party.
In February of 1801, a game of cards at a local tavern nearly ended John Rowan's career. John Rowan joined a group of men to play cards and an argument was incited with Dr. James Chambers over who was a better scholar of dead languages. The argument became bitter and developed into a physical fight. Two days after the fight, Chambers challenged Rowan to a duel. Rowan accepted the challenge. On February 3rd, both parties met outside of Bardstown and Rowan won the duel, shooting Chambers below the breast. Rowan rushed to Chambers, apologizing and offered to send his carriage to take Chambers to the town doctor. Chambers died the following day after requesting of his friends to not prosecute Rowan.
In 1804, Kentucky Governor Greenup appointed John Rowan as Kentucky's Secretary of State. Federal Hill was the primary home of the Rowan family until 1823 when a townhouse in Louisville, Kentucky was purchased. That same year, John was elected to the Kentucky House of Representatives. After 1823, the family divided their time between the townhouse and Federal Hill. In 1824, John was elected to the United States Senate and remained in office until 1830. After his Senate term, Rowan returned to Kentucky where he became the first president of both the Louisville Medical Institute and the Kentucky Historical Society.