Amthor was born in Stepfershausen, Thuringia, and was active as a schoolteacher, singer (tenor), viola player and choral conductor in nearby Bad Salzungen. Amthor's only compositions whose publication was noted in any Hofmeister publication up through the Handbuch of 1921 are two works for piano published in 1898 and 1899 in the Neue Musik-Zeitung.