Frank Esler was born at Copenhagen, New York on August 1, 1843, and was apprenticed to a saddle maker in Booneville, New York. Married in 1861 to Mary E. Jackson, he worked at his trade at Booneville until he enlisted in the Union Army in the summer of 1862. He mustered out after a year and spent the balance of the war as a contractor for cavalry supplies. In 1866, with his wife, Esler moved to Argenta, Montana Territory, where he speculated in mining and ran a small store which he called "Esler House." In 1869, he moved to Jefferson City (Jefferson County) where he failed in a number of business enterprises. In 1874, the Eslers moved to Bozeman (Gallatin County) where he established a saddlery business, eventually forming a partnership with Ferdinand Englefried. During this partnership, the firm was known as "Englefried and Esler." Frank Esler also became a director of the First National Bank in Bozeman during the mid 1880s. His date of death is unknown.
From the guide to the Engelfried and Esler Records, 1866-1889, (Montana State University-Bozeman Library, Merrill G Burlingame Special Collections)