William R Kostoff

William Reed Kostoff, father, grandfather, brother, and devoted public servant, passed away on Friday, March 20, 2026, at the age of 69, at Johns Hopkins Hospital, following a courageous battle with Amyloidosis. True to his determined and strong-willed nature, Bill fought until the very end while awaiting a heart, liver, and kidney transplant.

Born in Ann Arbor, Michigan, Bill grew up near the Canadian border, where he learned to sail, play ice hockey, and develop the competitive spirit that defined him throughout his life. He earned his undergraduate degree from the University of Notre Dame, where his Catholic faith deepened, and his MBA from the University of Michigan Ann Arbor. He began his family and his career as a financial analyst in Connecticut, later transitioning to Washington, D.C., where he served with distinction for 34 years at the U.S. Small Business Administration.

In later years, Bill found a great passion in competitive rowing at the Potomac Boat Club, winning numerous races and mentoring teammates of all ages. He was equally devoted to his faith as a parishioner of Saint Luke Catholic Church, where he participated in prayer groups and parish communities.

He is survived by his children, Corey Reed Kostoff and Jessica Rose Kostoff; son-in-law, Kenneth Lawrence Rusterholz; grandchildren, Aurora McAllister Rusterholz and Blaze Caleb Rusterholz; his brother, James Gregg Kostoff; ex-wife, Marianne McAllister; and ex-partner, Carol Dinion. He was preceded in death by his parents, Barbara Jane and Harold Richard Kostoff.

A Funeral Mass will be held at Saint Luke Catholic Church, McLean, Virginia, on Monday, March 30, 2026, at 11:00 a.m., followed by a reception.

He will be laid to rest at Mt. Hope Cemetery in Port Huron, Michigan.

In lieu of flowers, please send donations to The Amyloidosis Foundation https://amyloidosis.org/us/

Or Saint Luke Catholic Church https://www.saintlukemclean.org/egiving-with-parishsoft.html

Local arrangements are by Karrer-Simpson Funeral Home. To send condolences, visit karrersimpson.com

Be not afraid, Bill. May your spirit sail on in calm waters.