As a player at Western Kentucky, Oldham was a United Press and Associated Press All-American in 1949. He scored 1,006 points in his collegiate career. He later played for the Fort Wayne Pistons of the National Basketball Association.
Oldham coached Western Kentucky"s basketball team from 1964 to 1971, taking over for Diddle who retired in 1964.
Oldham finished 146-41 with a 78% winning percentage, leading them to four National Collegiate Athletic Association tournaments and an National Institute of Technology berth while establishing the Hilltopper"s place atop the Ohio Valley Conference standings. He led the Hilltoppers to the 1971 National Collegiate Athletic Association Tournament where they went to the Final Four and finished third overall (though years later the National Collegiate Athletic Association vacated their finish due to allegations that one of their players, Jim McDaniels, had agree to sign with a professional team prior to the end of the season).
On December 27, 2012, WKU honored Oldham in a pregame ceremony in which the court at EA Diddle Arena was named "John Oldham Court." Oldham was a player, assistant and head men"s basketball coach, and athletic director during his time at WKU.