 After mustering out later in 1865, Grubb returned to Burlington and established himself as a prominent iron manufacturer, taking over the family's business that went back to his great great grandfather, Peter Grubb Jr.He was president of the Lebanon Valley Furnace Company from 1867 until about 1911.In 1868, he married Elizabeth Wadsworth Van Rensselaer (1848–1886), daughter of an important family in the area.