Walker played in the minor leagues until 1889, and was the last African-American to participate on the major league level before Jackie Robinson broke baseball's color line in 1947. After his baseball career, he became a successful businessman and inventor. As an advocate of Black nationalism, Walker also jointly edited a newspaper, "The Equator", with his brother. He published a book, "Our Home Colony" (1908), to explore ideas about emigrating back to Africa. He died in 1924 at the age of 67.