Smith joined the Junior League in the 1950s, rising to president of the Los Angeles chapter in 1954 and western regional director in 1956. She served as national president from 1958 to 1960.
United Way, the American Red Cross, the National Endowment for the Humanities and the California Arts Commission.
A seasoned Washington wife, she was close to two Republican administrations. Her first husband, George William Vaughan, was assistant secretary of defense under President Eisenhower. Her second husband, William French Smith, was attorney general under President Reagan.
Nancy Reagan remembered Jean Smith in a statement Wednesday as "an incredibly kind and caring woman, and a good friend.… When Bill was named attorney general and they moved to Washington, D.C., Jean and I found ourselves reminiscing together on more than one occasion as we shared a little bit of homesickness for California."
Born in Los Angeles on Aug. 5, 1918, Smith attended Los Angeles and Beverly Hills high schools before entering Stanford University to study Greek and Latin. She met Vaughan at Stanford, graduated in 1940 and married him two years later. After World War II service, they settled in Los Angeles, where he prospered as an auto dealer and she raised their two children.
"When I went to Stanford, you got married, and then you did volunteer work. And I ran that into the ground," she quipped in a 1984 interview with The Times.
Noting that she "must have always wanted to run things," she quickly rose through the ranks of the Junior League, eventually overseeing 75,000 members in the United States, Canada and Mexico. In 1958 she was named a Times Woman of the Year.
She was married to Vaughan for 21 years, until his death in 1963. She is survived by their children, Bill of Santa Barbara and Merry Vaughan Dunn of Ojai, and five grandchildren.
After Vaughan died, she worked briefly in the public affairs office at San Francisco's Mark Hopkins Hotel, where she met William French Smith. They were married in 1964.
William became Ronald Reagan's personal lawyer, confidant, business advisor and, in 1981, attorney general. Jean served on the President's Advisory Commission on White House Fellowships.
They enjoyed the Washington social scene, where Jean drew some unwelcome attention from Washington Post columnist Richard Cohen.
"The ears of Mrs. William French Smith dangle earrings that cost more than a house," Cohen wrote in a 1982 piece attacking the Reagan administration for being insensitive to the needs of ordinary citizens.
Smith fired back in a letter critical of Cohen. She said her earrings were fakes that cost about $40, just enough to buy "a small doghouse, into which he could fit."