[1][2] In 1890, Allen became a professor of mathematics at Staunton Military Academy in Virginia.

[1] Allen worked for the Internal Revenue Service and then started practicing law in 1912.

They had five children, Herschel H., Wendell D., Edward Russell, Mrs. R. M. Wegner and Sarah Ruth (married Joseph Colvine Ocker).

[1][4][5][6] His son Wendell D. was a lawyer, assistant attorney general and served as president of the Maryland state school board.

[7][8] Allen died on February 3, 1927, at the age of 69, at his home on West Joppa Road in Towson, Maryland.