John M. Isgreen was born on 4 November 1853 to Andrew Jens Isgreen and Anna Mons Capson in Skonabeck, Sweden. He came to Utah Territory in 1859 and married Jane Dick on 14 February 1876. He worked as a salesman at the Tooele Co-op and was also a shoemaker, miller, and carpenter. He was the secretary of the Young Men’s Mutual Improvement Association in Tooele, Utah Territory, from 1877 to 1878. He died on 29 January 1932 in Tooele.
 Wilford Leo Isgreen, “John Mangus [Magnus] Isgreen,” in History of Tooele County (Salt Lake City: Daughters of Utah Pioneers, Tooele County, 1961), 502–503; Tooele Ward Manuscript History and Historical Reports, “Y.M.M.I.A.,” 11 Feb. 1877, CHL; John Magnus Isgreen, death certificate, 29 Jan. 1932, “Utah Death Certificates, 1904–1964,” database with images, FamilySearch, https://www.familysearch.org/ark:/61903/3:1:S3HY-6W23-JT5?i=2.