He batted and threw right-handed. The Saint Louis Cardinals drafted Johns in the sixth round of the 1992 amateur draft. The Cardinals traded him to the Milwaukee Brewers in 1997, and the Brewers sent him to the Baltimore Orioles a few months later.
In turn, the Orioles traded him to the Boston Red Sox in March 1998, where he finally made his major league debut as a pinch hitter for Jim Leyritz.
In his only major league plate appearance, he collected a walk. Johns played in the minor leagues from 1992 to 2000 for the farm teams of the Cardinals, Brewers, Orioles, Red Sox, Anaheim Angels, and Chicago Cubs.
In nine minor league seasons, Johns hit.249 with 27 home runs while stealing 106 bases. He played at least ten games at each of the four infield positions and six in the outfield.
They have two children, Kathleene Carroll Johns (2001) and Robert Keith Johns III (2005).