Arrived in the U.S. after 1810 (most likely 1822). Lived first in Detroit and in Berrien Co., Michigan before relocating to Racine, Wiscinsin. Mentioned in the Racine Advocate Aug. 6, 1844. In 1847, was one of three men to organize a Masonic Lodge there.

For many years collector of the port of Racine.

The Della and Isaac Ullmann House, at 731 Main St., was built in 1843. Isaac Ullman, a German-born wheat merchant who was involved in early community educational efforts, built the house. Ullmann served as both a Racine school commissioner in the late 1840s and one of the founders of Racine College in 1852.

See detailed biography of Isaac Ullmann by Laurence Emery Ullmann (draft Sept 1, 2015).
On the 6th of March 1824 Isaac purchased land in the village of Watertown in Jefferson County where he resided. Isaac was elected to represent St. Joseph County in the provisional state legislature in 1835. Michigan became a state in 1837. In 1843 the family moved to Racine, Wisconsin. 1860 census: Isaac and Delia living with their two youngest children, Frederick and Willis, in Racine. Isaac's occupation was recorded as Deputy U.S. Collector, and he owned $2500 in real estate and $400 in personal property. Frederick, at age fifteen, gave an oration at the Racine High School graduation of 1860.