[1] McGowan served in the United States Armed Forces during World War I in 1918, and then returned to the International League for 1919.

[2] Following the 1922 season, McGowan left the International League and joined the umpiring staff of the Southern Association, staying there until 1924.

His final game was on July 27, between the Chicago White Sox and the New York Yankees at Comiskey Park.

[5][6] McGowan spent time writing baseball-related newspaper articles in the offseasons, working for the New Orleans Item in the 1920s.

[8] He died at age 58 at his home in Silver Spring, Maryland, after suffering two heart attacks in less than a week.