Napier founded a chapter in Nashville of the National Negro Business League, which had been organized in Washington D.C. five years before; Napier served as president of the local chapter. In 1904, he co-founded the One Cent Savings Bank (later renamed the Citizens' Savings Bank and Trust Company and still operating as of 2017). Napier, Richard Henry Boyd, Preston Taylor, and others organized a strike against Nashville's segregated streetcar service that lasted from July 1905 until July 1906. Napier also presided over the Nashville Negro Board of Trade (now the Nashville Black Chamber of Commerce). He served on the boards of Fisk University, a historically black college located in the city, and Howard University. He also was instrumental in gaining legislative approval to found Tennessee Agricultural and Industrial State College (now Tennessee State University), a historically black college. He later served on the board of the Nashville Housing Authority, the first black person to do so. In 1911, Napier was appointed Register of the Treasury for William Howard Taft's administration. He was one of four African-American men appointed by Taft to high positions. They were known as the "Black Cabinet". He served until 1913, resigning in protest after Democratic President Woodrow Wilson broke with federal precedent to order racial segregation of workspaces, restrooms, and lunchrooms for federal employees of the Treasury Department. Wilson ordered similar segregation at the Post Office and the Bureau of Engraving and Printing to appease Southerners in his cabinet. In addition, in 1914 the Civil Service Commission began to require photographs with job applications, a means to screen out African Americans. Returning to Nashville from Washington, D.C., Napier resumed his law practice. Personal life While attending law school, Napier met John Mercer Langston, his wife Caroline, and their daughter Nettie. Langston was the founder and first dean of Howard University's law school. Napier married Nettie married in Washington, DC, and she moved to join him in Nashville where he had established a law practice. They adopted a daughter, Carrie. Napier was involved in extensive civic activities in Nashville. In 1910, he helped organize a Memphis, Tennessee chapter of Sigma Pi Phi, or Boulé, an organization of college-educated African-American men of high culture and status, along with Josiah T. Settle and some physicians in Memphis. The group said that "quality not numbers" was its aim for its membership. After five months of illness, Napier died in Nashville,