He was then sent to the Boston Red Sox, where he finished the 1919 season.
He went to the University of Colorado and Georgetown University. He was mainly a relief pitcher, although he occasionally started games. He broke into the Major Leagues when he was 22, on September 25, 1917.
He was playing for the New York Yankees at the time.
He played for the Yankees until 1919. McGraw went back to the Yankees in 1920.
Although, that was the last season he played with them. McGraw did not play in the Major Leagues for another five years.
Then, he made his comeback with the Brooklyn Robins.
Although he only pitched two games for them that year, he came back the next year, and played his first Major League season as a starting pitcher. He went 9-13 that year, a moderate season for someone converting from a relief pitcher to a starting pitcher. McGraw played part of the 1927 season with the Robins, pitching one game for them before playing the rest (and the majority) of the season with the Saint Louis Cardinals.
With the Cardinals, most games he pitched in were as a starting pitcher, with some relief appearances.
McGraw played two more seasons in the Major Leagues, both of which with the Philadelphia Phillies. He went back to relief pitching with them, although he received many decisions.
At 34 years old, in 1929, McGraw retired and played his final game on September 28. McGraw lived for nearly 50 more years.
He died on June 2, 1978, in Boise, Idaho, but was buried in Pueblo, Colorado.
He was 83 years old.