Herbert Brownell Jr., who as President Dwight D. Eisenhower's first Attorney General speeded desegregation by encouraging the President to name judges who vigorously carried out the Supreme Court's school integration decisions in the South, died yesterday in his home in Manhattan. He was 92..

The cause was cancer, said a daughter, Joan Brownell of Manhattan.

Mr. Brownell, a Nebraska native who was chairman of the Republican National Committee in the mid-1940's, helped engineer Eisenhower's first nomination for the Presidency. He then oversaw that Presidential campaign, in 1952, and became Attorney General the next year.

In that post he wielded great influence with the new and politically inexperienced soldier-President. As Mr. Brownell recalled in a 1993 interview, "Ike had a lot to learn about domestic policy." And Eisenhower confided to his diary in 1953 that he was devoted to Mr. Brownell and "perfectly confident that he would make an outstanding President."

Nonetheless, Eisenhower did not try to keep Mr. Brownell from resigning in 1957. By then the Attorney General had become, as the historian Stephen E. Ambrose later wrote, a political liability in the South who was "more insistent on integration than Eisenhower wanted him to be."

Earlier that year, Mr. Brownell was the President's chief counselor in the civil rights crisis that peaked with the sending of troops to enforce school integration in Little Rock, Ark. He also helped Eisenhower choose Earl Warren in 1953 to head the Supreme Court, a move that was followed by an era of major new decisions in civil rights and other areas.

It was Mr. Brownell who was mainly responsible for Eisenhower's filling Federal judicial posts in the South with more than a score of judges who were strong-willed, independent and sensitive to civil rights issues. These judges carried out the Supreme Court's historic desegregation decisions of 1954 and 1955, and sometimes made history by expanding on them. Four particularly influential ones were Elbert P. Tuttle, John Minor Wisdom, John R. Brown and Frank M. Johnson Jr.

Within the Cabinet, Mr. Brownell was one of the "Big Four" in Eisenhower's first term. The others were Secretary of State John Foster Dulles, Secretary of the Treasury George M. Humphrey and Secretary of Defense Charles E. Wilson.

The Attorney General also had a major voice in the selection of several other Cabinet members. But his relations were thorny with Congress and with former President Harry S. Truman.

Mr. Brownell provoked a furor in late 1953 by contending in a speech that Harry Dexter White, whom Truman had named as United States representative to the International Monetary Fund, "was known to be a Communist spy by the very people who appointed him." Truman denied the accusation and said Mr. Brownell was making the Justice Department a "headquarters for political skulduggery."

It was in the area of judicial selections and civil rights that Mr. Brownell was to leave a more enduring mark. These "choices of judges were profoundly influential in uprooting entrenched legal segregation in the South," said Ray Jenkins, a veteran Southern newspaperman who later became deputy press secretary to President Jimmy Carter.

Federal judges played a major role in desegregation largely because the Supreme Court ordered them to do so in its 1955 decision that carried out its opinion of 1954, Brown v. Board of Education, in which it ruled that racial segregation in public schools was unconstitutional.

Once the Supreme Court had taken its anti-segregation stand, Mr. Brownell said later, "We definitely tried to appoint judges who would be fair-minded and didn't have a record of pro-segregation support."

Some of the most far-reaching decisions were made by the United States Court of Appeals for the Fifth Circuit, which then handled appeals from Federal courts in 6 of the 11 states of the old Confederacy: Alabama, Florida, Georgia, Louisiana, Mississippi and Texas. The court handed down opinions that put blacks in state legislatures, on juries and in ballot booths in the Deep South.

Mr. Brownell also proposed a new civil rights bill, but the one that was eventually passed by Congress in 1957 was considerably weaker. It was, however, the first civil rights legislation enacted in Washington since the Reconstruction era.

He was often also outspoken about what was then widely called the threat of Communist sedition. In 1953 he declared, "I have dedicated myself and the Department of Justice to use every legal weapon to expose and punish the conspirators."

In that year he also recommended that Eisenhower reject calls for clemency for Julius and Ethel Rosenberg, who in 1951 had been convicted of conspiring to disclose nuclear secrets to the Soviet Union. "The Communists are just out to prove they can bring enough pressure to enable people to get away with espionage," Mr. Brownell told the President. The Rosenbergs were executed.

Although Mr. Brownell was outspoken on some issues, he was low-key in manner, and he tended to be cautious. This was apparent in 1971 when he and Louis Loeb, a fellow senior partner at the law firm Lord, Day & Lord urged The New York Times, then a client of the firm, not to publish a collection of secret Vietnam War documents, which became known as the Pentagon Papers.

The two men warned that publication would almost surely result in successful legal action by the Government. The Times disregarded the warning and published the Pentagon Papers. Lord, Day & Lord then dropped The Times and the paper was successfully defended against the Government suit by Prof. Alexander Bickel of Yale and the New York law firm of Cahill, Gordon & Reindel.

Herbert Brownell Jr. was born on Feb. 20, 1904, in Peru, Neb., the son of Herbert and May Brownell. The elder Mr. Brownell was later a professor of science education at the University of Nebraska.

Herbert Brownell Jr. received an A.B. degree and a Phi Beta Kappa key at Nebraska in 1924. In 1927 he graduated from the Yale University law school.

He was with the law firm Root, Clark, Buckner & Ballantine in Manhattan from 1927 to 1929, when he switched to Lord, Day & Lord, becoming a partner in 1932. He also went into New York Republican politics and served in the New York State Assembly from 1933 to 1937.

He directed Thomas E. Dewey's first successful campaign for governor of New York in 1942 and Dewey's unsuccessful Presidential campaigns in 1944 and 1948. He was chairman of the Republican National Committee from 1944 to 1946.

He scored a political coup at the Republican National Convention of 1952, where he was given much of the credit for the strategy used to outmaneuver backers of Senator Robert A. Taft of Ohio, Eisenhower's chief rival for the Presidential nomination. An aide to Taft later said that political combat against Mr. Brownell was "like wrestling with a cloud."

After resigning as Attorney General, Mr. Brownell returned to Lord, Day & Lord, where he stepped down as a senior partner in 1977. He was of counsel to the firm from 1977 to 1989.

In 1963 he was president of the Association of the Bar of New York City. He was also a close adviser to Mayor John V. Lindsay of New York in the 1960's.

After Richard M. Nixon was elected President in 1968, Eisenhower recommended in a memorandum that Mr. Nixon select either Mr. Brownell or Potter Stewart as Chief Justice to replace Earl Warren, who had stepped down. The post went instead to Warren E. Burger.

Mr. Brownell married Doris A. McCarter in 1934. She died in 1979. His 1987 marriage to Marion R. Taylor ended in divorce.

In addition to his daughter Joan, he is survived by another daughter, Ann Brownell Sloane of Manhattan; two sons, Thomas McCarter Brownell of Morristown, N.J., and James Barker Brownell of Philadelphia; a brother, Philip, of Asheville, N.C.; two sisters, Mary Helm of Manhattan, Kan., and Louise Trow of Ann Arbor, Mich.; three grandchildren, and two great-grandchildren.

Photo: Herbert Brownell Jr. (The New York Times, 1956)