Kruithof served as pastor of three churches: the Rey Avenue Reformed Church in Hawthorne, NJ, the Beverly Reformed Church in Wyoming, MI, and the First Reformed Church in Holland, MI. He was also professor of Bible and religion at Hope College from 1944-1947 and from 1957-1972. He retired from the faculty in 1972. Kruithof also served on the Hope College Board of Trustees from 1944-1950.
From the description of Papers, 1945-1990. (Joint Archive of Holland, History Research Center). WorldCat record id: 30343571