May 26, 1876, East Greenwich, Rhode Island.
September 30, 1918, France.
Meuse-Argonne American Cemetery and Memorial, Romagne-Sous-Montfaucon, France.
Alfred was the son of George Pomeroy Allen and Elizabeth Marshall Howe, and husband of Helen J. Warren Henderson.
Allen attended Selwin Hall, near Reading, Pennsylvania; Lehigh University, Bethlehem, Pennsylvania (1893–94), and graduated in medicine at the University of Pennsylvania (1898).
He began a career in neurology at the University of Pennsylvania and Philadelphia General Hospital. He was a fellow of the College of Physicians of Philadelphia; secretary (1908–09) and president (1910) of the Philadelphia Neurological Society; and secretary and treasurer of the American Neurological Association (1909–17).
Allen was also musically gifted, writing the words and music for an opera in his early years, and organizing the Savoy Opera Company for amateur productions of Gilbert and Sullivan operas. He also helped edit the 1911 Presbyterian Hymnal.
When he entered the Army, his gifts were quickly recognized, and he was for a while Commandant of the School of Automatic Arms in the Infantry School of Arms of the 79h Division at Camp Meade, Maryland. He was killed in action during World War I.