Wilkinson was the founder of the Kansas City Monarchs, one of the strongest and most stable franchises in Negro League history. The Monarchs began as the All-Nations Club, a multi-racial team that included blacks, Asians, Hawaiians, Hispanics, native Americans, whites, and a woman second baseman. Wilkinson signed Jackie Robinson to his first professional contract. Highly respected by his players and fellow owners, he was an innovator and the only white owner in the Negro National League when it was organized in 1920. In 1930, his Monarchs became the first pro team to use a portable lighting system for night baseball. The club won a dozen league championships between 1923 and 1950 and made four Black World Series appearances.