While the “H” in HOK indeed stands for Hellmuth, it was his uncle, George F. Hellmuth, who in 1955 co-founded Hellmuth, Obata + Kassabaum (later renamed HOK) in St. Louis with partners and fellow Washington University alumni Gyo Obata and George Kassabaum. Raised in Cleveland and educated at the University of Virginia and at Princeton University where he received his master’s in architecture, Bill Hellmuth began his career at SOM’s New York office and had little professional or personal ties to the Missourian city where what today is one of the largest architecture-engineering firms in the United States was established.

Bill Hellmuth pictured in 2000. Photo courtesy HOK

Hellmuth did eventually find his way to St. Louis in 1991 when he left New York to join HOK. After less than two years at the firm’s St. Louis headquarters, he was tapped by Obata, who died last year at 99, to lead the firm’s Washington, D.C., office. In 2005, he was named president of HOK, later becoming CEO in 2016 and, in 2017, firm chairman, while continuing to shepherd the D.C. studio as design principal.

“Gyo was very human and humble, and because of him there’s a lot of good Midwestern values imbued in HOK,” the firm recounted Hellmuth as telling the St. Louis staff during a 2019 office visit. “Be helpful to the people you’re working with, the people working for you and the people you’re working for. And be optimistic. Ours is not a profession for pessimists.”

The Consolidated Forensic Laboratory in Washington, D.C. Photo courtesy HOK

Hellmuth, described in the firm’s announcement as an architect who was “exceptionally optimistic about the ability of design to improve people’s lives,” led the design of numerous high-profile projects both in and around the nation’s capital including the National Air and Space Museum Steven F. Udvar-Hazy Center in Chantilly, Virginia; NOAA’s National Center for Weather and Climate Prediction in College Park, Maryland; Jenkins Hall Behavioral and Social Sciences Center at Morgan State University in Baltimore; the Consolidated Forensic Laboratory in Washington, D.C., and Constitution Square, a mixed-use project in Washington’s emerging NoMA neighborhood.

Abu Dhabi National Oil Company Headquarters in the UAE. Photo courtesy HOK

Further afield, notable continent- and typology-spanning projects designed by Hellmuth include Abu Dhabi National Oil Company Headquarters in the United Arab Emirates; the U.S. Embassy Chancery and Office Annex in Moscow; the Sheraton Inn Timika Guest House in Irian Jaya, Indonesia; the U.S. Embassy in Nairobi, and King Abdullah Petroleum Studies and Research Center and Residential Community in Riyadh, Saudi Arabia. In total, Hellmuth led projects in 20 countries with 29 of them winning awards from the American Institute of Architects. 

The National Air and Space Museum Steven F. Udvar-Hazy Center in Chantilly, Virginia. Photo courtesy HOK

“He was happiest when working with one of our designers at their desk,” said Susan Klumpp Williams, managing principal of HOK’s D.C. office, of her late colleague. “His passion for design and our profession inspired those of us who had the privilege of working closely with him.”

Hellmuth is survived by his wife, Nancy, a son and daughter, and two grandchildren.