From the OHS PC Database, derived from A Guide to North American Organbuilders by David H. Fox (Organ Historical Society, 1997) -

Born 1 March, 1826 in Gotenborg, Sweden; immigrated to the United States, 1850; briefly with firm in New York City, New York; with William B. D. Simmons firm of Boston, Massachusetts; in San Francisco, California, by 1864; established his own firm by 1875; relocated to Minneapolis, Minnesota, 1891; returned to San Francisco, 1893; retired c. 1900; died 9 September, 1907 in California.

Staff: (Oscar Bahlinger?).

Sources:

• Jim Lewis.
Organ Handbook (OHS Press, 1988), p12.
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From the OHS Database Builders Listing editor, October 28, 2016. —

"Another immigrant organbuilder was John Eric Bergstrom (1826-1907), who came to this country from Sweden. He trained in his native country before coming to these shores in 1850; he worked for a time with a Boston organbuilder before moving to San Francisco. He is listed in the directories there as an organbuilder as early as 1864, but he was perhaps working for someone else. By 1875, he seems to have had his own shop, and he was firmly established by 1880. In 1891, he transplanted his business to Minneapolis, Minnesota; he built several organ for churches in that area, but apparently regarded the prospects for additional work as unpromising, and returned to San Francisco in 1893. From 1879 until around the turn of the century, the firm of John Bergstrom & Sons built more than 66 organs, including several for locations in Hawaii. About 1900, Mr. Bergstrom retired, and his sons relocated to Hawaii, where they opened a music store."

Alan Laufman, Organ Handbook (OHS Press, 1988).