DuVal, a Democrat known for his hard work on multiple issues and as a party-builder, rose quickly to leadership when he was first elected to the Virginia General Assembly.
"He was the essence of what gentlemanly conduct means," said Joseph V. Gartlan Jr., who served alongside DuVal in the Virginia Senate. "He was always courteous, always obliging. He was never personally angry. He had passion, but never let it get directed at individuals."
Gartlan said DuVal was an environmental and human services champion who looked out for consumer interests.
"His sense of values, in terms of what the legislature is supposed to do, and mine were almost identical," said Gartlan, who became dean of the Northern Virginia delegation after DuVal's retirement.
Gartlan said DuVal was an avid tennis player who often escaped to Florida's Gulf Coast to fish after the legislature's long winter sessions.
"The Senate lost a great guy when he decided to retire, and all of Virginia lost something very meaningful with his passing. ... I loved the guy," Gartlan said.
DuVal was the "gentleman giant of Northern Virginia in last half of the 20th century," said longtime friend Arthur Arundel, chairman of Times Community Newspapers.
Fairfax County Board Chairman Katherine Hanley said she was stunned.
"He came to my recent fund-raiser," she said. "He was an exceptional role model for everyone in public service. He was so knowledgeable, so diligent and always such a gentleman."
DuVal is survived by two sons, Clive Livingston DuVal III and Daniel DuVal, and a daughter, Susan Phipps, and three grandchildren.
Preceding him in death was his wife, Susan, and a son, David, who died in 1988.
DuVal's rise to local fame began about 1962 when he was a leader in the highly publicized fight to halt construction of the proposed Merrywood high-rise apartments along the banks of the Potomac River on Chain Bridge Road.
The project had been approved by the Fairfax County Board of Supervisors, but DuVal and others led a fight to halt the project along with then-U.S. Secretary of the Interior Stewart Udall.
Eventually, owners of the land agreed to reduce the size of the project in return for a scenic easement payment of about $750,000. That agreement led to the building of the Merrywood town house project on the site.
He then easily won election to the state house and was later elected to the Virginia Senate.
DuVal and his wife purchased part of what would become the 52-acre historic Salona estate in 1952 with a payment of about $50,000.
Salona, the house itself, is a major historic site in Fairfax County. It is off Chain Bridge Road between downtown McLean and Trinity United Methodist Church.
Salona is the house that sheltered President James Madison on the night of Aug. 24, 1814, when British troops burned the U.S. Capitol, the president's house and other buildings in Washington, D.C.
After the DuVals moved in, the estate quickly became the scene of major social and political gatherings, attracting multiple appearances from political leaders and a visit by Democrat Jimmy Carter when he was running for president.
The DuVals long ago deeded eight acres around the house as a permanent easement never to be developed.
There is a temporary agricultural and forestal easement, granted by Fairfax County, on the other 42 acres.
Susan DuVal died Jan. 4, 1997. In her honor, DuVal built the Susan B. DuVal Art Studio for The McLean Project for the Arts within the McLean Community Center.
"It was an exceedingly generous gift in loving memory of his wife," recalled Evelyn Fox, who chaired the Community Center Governing Board when the studio opened.
"The studio allowed MPA to greatly expand art classes and freed the gallery for more exhibits," Fox said.
Fox also noted that DuVal had "always demonstrated a concept of community" in McLean. "For many years he used his fields (at Salona) for Easter egg hunts," she said.
Staff writers Marcia McAllister and Jerry Schanke contributed to this report.