He played in Major League Baseball (MLB) from 1909 through 1921 for the Pittsburgh Pirates, St. Louis Cardinals, and Philadelphia Phillies.

In his rookie season, he drove in 87 runs and helped Pittsburgh win the National League pennant and their first World Series title.

In the years since his death (beginning at least as early as a 1935 story penned by one-time Phillies teammate Stan Baumgartner), Miller's nickname has frequently been attributed to a simple misinterpretation of teammate Honus Wagner's heavily accented response, "That's Miller.

[4] Miller became manager of a Pacific Coast League team, the San Francisco Seals, in 1922.

[5] The following season, the Seals were league with by ten games when, on July 23, Miller was forced to step down after contracting tuberculosis.