He played second base in Major League Baseball for the Philadelphia Athletics, Cleveland Naps, Chicago White Sox, and Cincinnati Reds.

Rath attended Swarthmore College but did not play for the Garnet Tide, as the school had not yet established a baseball program, but he did pledge the Delta Upsilon fraternity during his tenure.

After playing for the Reading Pretzels, Rath began his major league career as a bench player for the Philadelphia Athletics in 1909, appearing in seven games.

He was traded in the middle of the 1910 season to the Cleveland Naps because the Athletics already had star second baseman Eddie Collins.

In his comeback season he had a .264 batting average, drew 64 walks, and was the leadoff hitter for the pennant-winning Reds.

[3][4] After his retirement from baseball, Rath ran a sporting goods store in Upper Darby Township, Pennsylvania.