From the OHS PC Database, derived from A Guide to North America Organ Builders by David H. Fox (Organ Historical Society, 1991) —

Born December 8, 1878; son of Felix F. Schoenstein, brother of Erwin A., Louis J., and Otto H. Schoenstein, father of Paul and Leo G. Schoenstein Jr.; with Felix Schoenstein & Sons of San Francisco, California; with Farrand & Votey of Detroit, Michigan; with Müller & Abel of New York City, New York; with Aeolian firm of Garwood, New Jersey; with Odell firm of New York City, New York; with Eilers Music Co. (representatives of W. W. Kimball of Chicago, Illinois) in San Francisco, California, 1907-1914; with Robert-Morton Co. of Van Nuys, California, c. 1925, superintendent; representative of the Möller firm of Hagerstown, Maryland, 5 years; with Bergstrom Music Co. of Honolulu, Hawaii, 1940s; died August 26, 1951 in San Francisco, California.

Sources:

• The Bicentennial Tracker (Richmond, Va., The Organ Historical Society, 1976), 118.
• The Diapason October 1951, 7.
• Louis J. Schoenstein, Memoirs of a San Francisco Organ Builder (San Francisco: Cue Publications, 1977), 264, 282, 373, 381.
• Elizabeth Towne Schmitt.

From Organ Database Builders editor Stephen Hall, November 13, 2019. —

Most of the Schoestein organbuilders worked for a period with larger firms in the eastern United States, then returned to the family firm. This gave them broader experience, allowed them to keep up with new trends, and made it easier for the Schoenstein firm to service works by other builders. Louis J. Schoenstein seems to be the only one who did not return to the family firm, instead working for a succession of firms around the country.