He was born in Taos to Joseph Henry Grothoff and Johanna Catherine Forck Grothoff. He was married on June 18, 1949 in Jefferson City to Lavern Edith Knernschield who survives at the home. Other survivors include six sons, James B. Grothoff, Wardsville; Steven O. Grothoff, Daniel J. Grothoff, and Gary L. Grothoff, all of Jefferson City; Mark A. Grothoff, Columbia; and Douglas E. Grothoff, Holts Summit; a daughter, Karen M. Dumey, Jefferson City; seventeen grandchildren; two great-grandchildren; a brother, Richard Grothoff, Jefferson City; and two sisters, Helen Bisges, Wardsville; and Clara Eiken, Taos. He was preceded in death by a granddaughter, Stephanie Grothoff; a great-grandson, Michael Rea; a sister, Joan Richards; and two brothers, Harold Grothoff and Frances Grothoff. He was employed with Rost Sheet Metal, Harold G. Butzer, Inc. and for many years was maintenance supervisor at St. Peter Catholic Church until retiring in 1991. He was a member of St. Peter Catholic Church; Holy Name Society; Sheet Metal Workers Union; and was a volunteer with the Vogelweid Special Learning Center. Memorials are suggested to Vogelweid Special Learning Center; St. Peter Improvement Fund; or Masses. He was a U.S. Navy veteran of World War II, receiving the Victory Medal. He was a 1944 graduate of Taos High School.