Leonard L. Silverstein, a Washington lawyer and arts patron who started a series of prominent tax-law guidebooks and became a member of the city’s cultural and fundraising firmament, died Feb. 14 at his home in Bethesda, Md. He was 96.

The cause was complications from a lung ailment, said his son, Thomas Silverstein.

As a young, Harvard-educated legal adviser to the Treasury Department, Mr. Silverstein helped shape the Internal Revenue Code of 1954, a massive overhaul of the federal income tax system. In 1959, he created Tax Management Porfolios, authoritative texts for the nation’s accounting firms and which today are part of the Bloomberg media empire.

The next year, he co-founded Silverstein and Mullens, a firm specializing in tax law and estate planning. In 2000, it became a division of what is now the Pittsburgh-based Buchanan Ingersoll & Rooney. Until his death, Mr. Silverstein worked at the merged operation. Among his clients were Fortune 500 companies in fields as disparate as aerospace and entertainment.

In addition to corporate board memberships, Mr. Silverstein served on government-sponsored panels that sought to foster the well-being of cultural institutions.

Along with Frank Sinatra and Kennedy Center Chairman Roger L. Stevens , Mr. Silverstein sat in the 1980s on the President’s Committee on the Arts and the Humanities, where he promoted corporate philanthropy.

He was board president of the National Symphony Orchestra Association at a time when the NSO was beset by multimillion-dollar shortfalls. He helped management and musicians reach an agreement that included a one-year moratorium on wage increases and secured a line of credit for the orchestra from American Security Bank, where he was a director.

Notable deaths in 2018 and 2019: Nipsey Hussle, George H.W. Bush, Stan Lee, John McCain, Aretha Franklin and other famous faces we’ve lost

Nipsey Hussle, a Grammy nominated rapper who sought to revive South Los Angeles, died at age 33 on March 31. Read the obituary (Matt Winkelmeyer/Getty Images for Warner Music)

Washington, he lamented, was a city with no Brahmins (like the Cabots of Boston) and few philanthropists (like the Meyerhoffs of Baltimore) who channeled their wealth into first-class symphony orchestras in their respective communities.

“There was a fellow named Cabot who lived in Georgetown for 30 years, died a while ago and left a million dollars to the Boston Symphony,” he told The Washington Post in 1982. “Naturally, that breaks my heart.”

Mr. Silverstein also lamented the NSO’s lack of landmark recordings that might have generated greater ticket sales, as well as the lukewarm support it received from city government and businesses.

But the orchestra, he noted, had a formidable asset in Mstislav Rostropovich , the Russian-born cellist who had been hired as music director in 1977. His star power and international stature were credited with revitalizing the NSO during his 17-year tenure. The Kennedy Center took the NSO under its auspices in 1986, helping rescue the orchestra from continued fiscal woes.

“Slava is terrific in lending himself to any sort of legitimate promotional activity,” Mr. Silverstein told The Post, using the musician’s nickname. “Not all star conductors are like that. Von Karajan, they tell me, you can’t even talk to.”

Leonard Lewis Silverstein was born in Scranton, Pa., on Jan. 21, 1922; his father, a lawyer, became city solicitor. After receiving a bachelor’s degree from Yale University in 1943, he served in the Navy in the Pacific during World War II. He graduated from Harvard Law School in 1948 and, in Washington, briefly worked for the IRS and as special tax counsel to the Small Business Administration. He opened his law practice with Richard A. Mullens, who died in 2010.

In 1951, he married Elaine Wise. Besides his wife, of Bethesda, survivors include two children, Thomas Silverstein and Susan Scott, both of Washington; a sister; and four grandchildren.

Mr. Silverstein served at points as board vice chairman of the John F. Kennedy Center for the Performing Arts, trustee of the Corcoran Gallery of Art, treasurer of the James Madison Council — an elite group of Library of Congress donors — and chairman of the U.S. Advisory Commission on Public Diplomacy, a bipartisan group whose duties include oversight of the U.S. Information Agency.

He also chaired the Rostropovich-Vishnevskaya Foundation, founded by Rostropovich and his wife, soprano Galina Vishnevskaya , to raise money for medicine, food and equipment for children’s hospitals and clinics from Russia to the West Bank and Gaza.

Mr. Silverstein, who began taking French lessons as an adult, was a past president of the Alliance Française of Washington and the French-American Cultural Foundation — endeavors that brought him honors from the French government.

His other board memberships included the White House Historical Association and the Choral Arts Society of Washington.

As a private creative outlet, away from the ego of executive suites and the arcana of the tax code, Mr. Silverstein was a watercolorist and played piano.