Beginning in 1955, when he came to Washington, Mr. Barrett was one of the first civil rights lawyers in the government. He was part of the Justice Department’s Civil Rights Division when it was created in 1957 and had a major role in many celebrated legal landmarks, including the desegregation of Little Rock’s Central High School in the 1950s, James Meredith’s enrollment as the first African American student at the University of Mississippi and the integration of interstate buses by the Freedom Riders of the early 1960s.
Mr. Barrett, who was 89 when he died May 28 at Howard County General Hospital of pneumonia, seldom made headlines on his own. But for more than a decade, he was at the forefront of perhaps the most momentous movement for social change in the nation’s history.
“He made an enormous impact as a government lawyer in enforcing the civil rights laws,” John Doar, the top lawyer in the Civil Rights Division in the 1960s and recipient of the Presidential Medal of Freedom last month, said in an interview. “I had such confidence in him. I felt he had a much better grasp of civil rights law than I did.”
Mr. Barrett was an assistant district attorney in Oakland, Calif., when a former colleague invited him to join the Justice Department. Civil rights law was still in its infancy.
In 1957, Mr. Barrett worked alongside Thurgood Marshall — who later became the first African American justice of the U.S. Supreme Court — on the case in Little Rock, in which the governor used the National Guard to prevent the school from integrating.
Often, however, Mr. Barrett was on his own, exploring a new legal field with few precedents. Armed with little more than the force of law and sheer moral courage, he performed much of his work in the face of intimidation, anger and fear.
At home in Chevy Chase, Mr. Barrett’s children knew little about their father’s contributions to civil rights.
“He didn’t talk about that,” his son David Barrett said. “That’s something he would downplay.”
St. John Barrett was born May 21, 1923, in Santa Rosa, Calif., where his father was a lawyer. The younger Mr. Barrett — whose first name derived from his mother’s maiden name — grew to be a lanky 6-foot-4 and was known from an early age as “Slim.”
He graduated from Pomona College in Claremont, Calif., in 1943. He contracted meningitis, which kept him out of the military during World War II, and he worked as an engineer at an aircraft plant in Santa Monica, Calif. He graduated from law school at the University of California at Berkeley in 1948.
When he traveled overseas in 1951, Mr. Barrett carried with him a letter of introduction from Earl Warren, the governor of California, who became chief justice of the Supreme Court in 1953. Both men were Republicans and had worked as prosecutors in Alameda County, Calif.