He played in Major League Baseball as a right-handed pitcher for the Pittsburgh Pirates from 1907 through 1910.

He defeated the Brooklyn Superbas 2–1 at Pittsburgh's Exposition Park on September 20, 1907, one week after pitching a 4–0 shutout against the St. Louis Cardinals in his major league debut.

The Pirates' home stadium in between, Forbes Field, had not witnessed a no-hitter in its 61-year (mid-1909–mid-1970) history.

Maddox was also the last Pirate to win his first 4 career starts (in 1907) until the feat was matched by Gerrit Cole in 2013.

[1] William F. Kirk of the New York American in 1908 called Maddox a "a well formed youth with a face like a dried apple.