LOS ANGELES, JULY 17 -- The board of the Los Angeles Unified School District, second largest in the nation, has moved for rapid change in a system deluged with immigrant children with its sudden appointment of the city's first Hispanic school superintendent.

The board's decision late Monday to appoint veteran deputy superintendent William Anton, 65, to succeed superintendent Leonard Britton, who last week announced plans to resign in 1991, caught many teachers and administrators by surprise. Britton, the former head of the Dade County, Fla., schools, had been selected in 1987 after a lengthy national search, and few predicted the board would so rapidly install a replacement.

But the huge district has been shaken by last year's teacher strike and a surge of Latin American immigrant children that has swollen enrollment to 610,000, nearly 62 percent Hispanic. Leticia Quezada, the board's only Hispanic, and Rita Walters, its only black, had been critical of Britton and last year helped persuade Anton, who has worked in the district 38 years, to drop plans to retire.

"We felt that with all the problems that we faced, we needed someone who had the confidence of the teachers, the administrators, and particularly the community," said Quezada.

The board voted 5 to 2 to buy out the last year of Britton's contract, at a cost that may exceed $200,000, after a closed-door meeting that lasted most of the day. The vote to give Anton the $164,555-a-year superintendent's job was 6 to 1.

The only vote against Anton came from board member Julie Korenstein, representing part of the predominantly non-Hispanic white San Fernando Valley, where many parents have removed their children from public schools or sought to create a new district separate from the rest of the city. Korenstein said she objected to giving Anton a three-year contract, with a provision for review after two years, without looking at other possible candidates.

Anton, who began his career as an elementary school teacher in 1952, has been considered by many teachers, Hispanic and otherwise, to be part of a conservative central administration resistant to new ways of breaking city students out of a cycle of poverty and low educational standards. He told reporters after the vote Monday he was optimistic about the future of the district and felt he had an advantage in knowing so many of the key leaders.

He immediately telephoned Helen Bernstein, newly installed president of the powerful United Teachers-Los Angeles, to promise cooperation. Bernstein had complained that Britton's announcement last week left the district with a lame-duck superintendent.

Besides its Hispanic majority, the district student body is about 16 percent black, 15 percent white and 6 percent Asian American. Classroom crowding has been so extreme the entire system is about to go on a year-round schedule, and a budget crisis in Sacramento has raised the threat of a decline in funds.

Anton's appointment means both Los Angeles and New York, the nation's largest school district where Joseph A. Fernandez is chancellor, are headed by Hispanics.