This thesis is a career biography, and chronicles the life and service of Stephen Clegg Rowan, an officer in the United States Navy, and his role in the larger picture of American naval history. The author has utilized mainly primary sources, including a journal kept by Rowan himself (transcribed from a microfilm copy of a handwritten journal, 900+ pages), and the Official Records of the United States military branches that were kept during the course of the Civil War. Rowan's wartime experiences and the contributions he made during the Second Seminole War, the Mexican War, and the Civil War form the framework of this paper. It also covers the interim periods, during which Rowan participated in other pursuits of the US Navy, including exploration and diplomatic ventures. It concludes with a brief overview of Rowan's accomplishments while serving in the Navy, and his family's continued military service. This thesis outlines the larger role played by the Navy in each engagement, with particular emphasis on the theaters of war in which Rowan participated (the Californian and Mexican west coast during the Mexican War, and his riverine and coastal services during the Civil War). It also examines the broader impact and influence that these experiences had on Rowan as an individual and on the navy as a whole.