Clarence B. Jones, a confidant, lawyer and speechwriter for the Rev. Dr. Martin Luther King Jr. during the civil rights struggles of the 1960s, who helped plan the March on Washington and drafted part of Dr. King’s celebrated “I Have a Dream” speech, died on Friday in Cupertino, Calif. He was 95.

His death, at an assisted-living facility, was confirmed by his son, Clarence Jr.

A brilliant organizer and a member of Dr. King’s inner circle, Mr. Jones planned protest campaigns; raised funds for Dr. King’s Southern Christian Leadership Conference; and coordinated legal strategies to challenge discriminatory laws, defend arrested demonstrators and fight lawsuits against their leaders.

He was one of the lawyers who represented four Black ministers in a seminal case of libel law, The New York Times v. Sullivan, in which the United States Supreme Court held that a public official could not win damages for criticism of his official performance without proving that published statements were made with deliberate malice. It was a landmark victory for the constitutional guarantee of freedom of the press, and cleared the way for reporting on widespread disorder and civil rights infringements in the South without fear of libel actions.

It was also a clarifying victory for civil rights leaders. “We regarded the suit as an effort to politically discredit the leadership of the direct action civil rights movement of Dr. King,” Mr. Jones told law students at the University of San Francisco in 2012. “The political objective of the lawsuit was to bankrupt and decapitate the civil rights leadership.”

The many-sided Mr. Jones was at various times a California entertainment lawyer, the first Black partner in a Wall Street brokerage on the New York Stock Exchange, the principal owner and publisher of The New York Amsterdam News, a co-owner of the radio station WLIB-AM in Harlem, a university professor and the author of books on civil rights.

He also investigated the bloodiest prison uprising in the nation’s history — the 1971 inmate revolt at Attica, N.Y., which was crushed by National Guard troops and state police officers on Gov. Nelson A. Rockefeller’s orders. As Mr. Jones and Representative Herman Badillo later said in sworn statements, they were unable to persuade the governor of alternatives to retaking the prison, in an assault that led to the deaths of 29 prisoners and 10 hostages and years of lawsuits and recriminations over responsibility for what a court called an “orgy of violence.”

Mr. Jones was often an unseen hand behind historic events. In 1963, he helped plan demonstrations in racially-segregated Birmingham, Ala., that exposed to a shocked nation the brutality of authorities who turned high-pressure fire hoses and snarling dogs on hundreds of children and adult protesters, many of whom, including Dr. King, were hauled off to overflowing city jails.

Later, when Dr. King wrote his classic statement on racism, the “Letter From Birmingham Jail,” it was Mr. Jones who smuggled it out — a “manuscript” scribbled first on scraps of paper and in the margins of newspapers, and later on Mr. Jones’s notepads. The bits and pieces were assembled and edited for publication by the Rev. Wyatt Tee Walker.

That summer, Dr. King, Mr. Jones and others — including Roy Wilkins, James Farmer, John Lewis and the political strategist Stanley Levison — met often at Mr. Jones’s apartment in the Riverdale neighborhood of the Bronx to plan the March on Washington for Jobs and Freedom and discuss ideas for the speech Dr. King would deliver at the Lincoln Memorial.

There were several versions, written at different times, of what became the “I Have a Dream” speech. Dr. King wrote a final draft with Mr. Jones and Mr. Levison. They called it “Normalcy — Never Again.” There was no reference to a dream and little of the stirring rhetoric for which Dr. King is remembered.

“The logistical preparations for the march were so burdensome that the speech was not a priority for us,” Mr. Jones recalled in a memoir, “Behind the Dream: The Making of the Speech That Transformed a Nation” (2011, with Stuart Connelly).

On Aug. 28, 1963, 250,000 people crowded onto the National Mall. The day was a show of support for civil rights legislation proposed by President John F. Kennedy, and the speakers had agreed to avoid incendiary remarks that might derail it.

Dr. King’s speech began quietly, with an analogy about America defaulting on a promissory note to its minority citizens, and Mr. Jones, standing nearby, recognized it as one of his contributions. Then, partway into the speech, the gospel singer Mahalia Jackson shouted, “Tell ’em about the dream, Martin.”

Dr. King paused. “Martin clutched the speaker’s lectern and seemed to reset,” Mr. Jones recalled. Then Dr. King put his text aside, dropped his assessment of current injustices and launched into a soaring, improvised peroration on his vision of America as a land of freedom and equality rising from slavery and hatreds.

“I have a dream,” he declared, “that one day this nation will rise up and live out the true meaning of its creed: ‘We hold these truths to be self-evident, that all men are created equal.’ I have a dream that one day on the red hills of Georgia the sons of former slaves and former slave owners will be able to sit down together at the table of brotherhood.”

“I have a dream,” he continued, “that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character. I have a dream today.”

Mr. Jones later obtained, and signed over to Dr. King, the registered copyright for one of the most heralded speeches of the century.

Clarence Benjamin Jones was born in Philadelphia on Jan. 8, 1931, to Goldsborough and Mary (Toliver) Jones. His father was a gardener and chauffeur, and his mother was a maid.

To give him a better life, his parents placed him in a foster home in Palmyra, N.J., when he was 6. He attended a boarding school in Cornwells Heights, Pa., and graduated from Palmyra High School in 1949, and from Columbia University in 1953. The Dr. Clarence B. Jones Institute for Social Advocacy was dedicated in his honor in 2017 at Palmyra High School.

Drafted by the Army, he refused to sign a loyalty oath, spent 21 months at Fort Dix, N.J., and received an “undesirable” discharge in 1955. But he sued and won an honorable discharge.

In 1956, he married Anne Norton, whose parents had founded the book publisher W.W. Norton & Company. They had four children, Christine, Alexia, Clarence Jr. (known as Ben) and Dana, and divorced in 1970. Anne Jones died in 1977.

A 1976 marriage to Charlotte Schiff ended in divorce in 1984. In 1990, he married Jennifer Poznanski; they had one daughter, Felicia, and were divorced in 2000. He is survived by his five children and his longtime partner, Lin Walters.

He received a law degree from Boston University in 1959, moved to Altadena, Calif., and practiced entertainment law. In 1960 he helped defend Dr. King in an Alabama tax perjury case, returned to New York and became a fund-raiser and lawyer for Dr. King and the Southern Christian Leadership Conference.

His most notable case was the libel suit that arose after The Times published an advertisement in 1960 soliciting funds for Dr. King’s defense in the tax perjury case. Dr. King was cleared, but the suit continued. The ad cited racial conditions in the South. While it named no public officials, L.B. Sullivan, a public safety commissioner in Montgomery, Ala., accused The Times and four Black ministers who had signed the ad of defaming him. Many lawyers worked on the case, and Mr. Jones joined the ministers’ defense team.

After an Alabama jury awarded Mr. Sullivan $500,000, The Times and the ministers — the Revs. Ralph Abernathy, Fred Shuttlesworth, S.S. Seay Sr. and Joseph E. Lowery — appealed, and the Supreme Court held in 1964 that public officials must prove “actual malice,” showing that a publisher knew a statement was false or acted in reckless disregard of its truth or falsity. The ruling undercut some $300 million in libel actions pending in the South against news organizations.

In 1967, Mr. Jones became a vice president of the Carter, Berlind & Weill brokerage and the first Black partner of a stock exchange member. After Dr. King’s assassination in 1968, he turned increasingly to business. In 1971, he and Percy E. Sutton, the Manhattan borough president, led Black groups that bought The New York Amsterdam News, the nation’s largest Black community-based newspaper, and WLIB, which served largely Black audiences. Mr. Jones was the newspaper’s publisher for three years.

When inmates seized hostages and cellblocks in the state prison at Attica in 1971, Governor Rockefeller named Mr. Jones and Mr. Badillo as on-the-scene observers. But both took on larger roles during and after the crisis. They tried unsuccessfully to dissuade Mr. Rockefeller from ordering the assault that retook the prison. Mr. Jones, later appointed chairman of an investigative panel to protect the inmates’ constitutional rights, quoted witnesses as saying that some were beaten and others killed while trying to surrender.

In sworn statements in 1989 in support of an Attica prisoners’ lawsuit, Mr. Jones and Mr. Badillo said that the governor, who spoke to them by phone, had been indifferent to their warnings of likely mass killings if the police moved in, to alternatives they suggested to retaking the prison by force, and even to the fate of the inmates and hostages.

The governor, Mr. Jones said, “clearly accepted the inevitability of a massacre.” A federal appeals court dismissed the prisoners’ suit against the Rockefeller estate, saying the governor’s actions were not unlawful. But the state later paid millions to settle damage claims by inmates and their families.

Mr. Jones wrote “What Would Martin Say?” (2008, with Joel Engel), and “Uprising: Understanding Attica, Revolution and the Incarceration State” (2011, with Stuart Connelly).

In recent years, Mr. Jones had lectured widely, taught at the University of San Francisco and was a resident scholar at Stanford University in Palo Alto. In 2018, Mr. Jones and Jonathan D. Greenberg co-founded the Institute for Nonviolence and Social Justice at the University of San Francisco to foster the teachings of Dr. King and Mohandas K. Gandhi. In 2024, he was awarded the Presidential Medal of Freedom, the nation’s highest civilian honor, by President Joseph R. Biden Jr.

In an interview with The Free Press that year, Mr. Jones recalled telling Dr. King about what made him a talented speechwriter.

“I hear your voice in my head,” Mr. Jones said. “I hear your voice in perfect pitch.”