After a brief stint as a vaudeville entertainer in New England, she made her professional opera debut in France in 1898. She then became a member of the Metropolitan Opera from 1900 to 1919 and again from 1927 to 1929.
She was also active as an opera singer in Boston, Chicago, and California. She recorded extensively for Victor Records and Columbia Records in the early decades of the 20th century. She was married to composer Sidney Homer for 52 years, and composer Samuel Barber was her nephew.
Homer sang a broad repertoire which encompassed works from the French, German, and Italian repertoires.
Louise Homer recorded several Christian hymns in duet with Alma Gluck.