He was also a professional boxer and trainer, and his nickname may have resulted from the need to distinguish him from the heavyweight champion Jack Johnson.

"[4] Johnson played for the Chicago Union Giants from 1903 to 1905 and again in 1907, his teammates including George Hopkins, Albert Toney, and Joe Green.

He founded and managed the Topeka Giants in 1906, taking them on a tour of Nebraska, Iowa, Illinois, Missouri and Kansas.

Fortune J. Weaver was also an owner of the KC Royal Giants and was president of the Afro-American Realty and Investment Company.

Johnson wrote: "It certainly has been proven from the big leagues on down to the minors, that there is nothing in the world that beats organized baseball and harmony..."[8][9] Johnson left the Kansas City Royal Giants after the 1910 season and returned to manage the Kansas City Giants in 1911.