In football, Cumberland Jr. was a star player and manager for semi-pro sandlot teams in the Pittsburgh area prior to 1910, including the Delaney Rifles and the Collins Tigers.

"The mystic wand of Posey ruled basketball with as much eclat as 'Rasputin' dominated the Queen of all the Russias", observed the Harlem Interstate Tattler in 1929.

Posey led Homestead High to the 1908 city championship, played basketball at Penn State for two years, moved to the University of Pittsburgh where he earned a pharmacy degree in 1915,[2] and formed the famous Monticello Athletic Association team that won the Colored Basketball World's Championship in 1912.

He later played varsity basketball for Duquesne University, under the name "Charles Cumbert", and led the Dukes in scoring for three seasons through 1919.

He retired from basketball in the late 1920s to focus exclusively on the business of baseball and on his weekly sports column in the Pittsburgh Courier, "In The Sportive Realm."

In a quarter-century running the team, he built it into one of the powerhouse franchises of black baseball, winning numerous pennants, including nine consecutively from 1937 to 1945.

Posey, an aggressive talent seeker with the Grays, at one time or another had over a dozen current Negro leagues Hall of Famers playing for him.

He also was a frequent critic of the league, both before and after joining it, in his regular sports columns for the Pittsburgh Courier, a leading black weekly newspaper.