The exclusive Madeira School in McLean yesterday named the first headmaster in its 75-year history, replacing resigned headmistress Jean Harris, now on trial on a charge of murdering Scarsdale Diet doctor Herman Tarnower.

Charles McKinley Saltzman II, a Harvard-educated administrator of a private school in New Orleans, was selected from nearly 100 applicants, according to a Madeira spokesman. He will assume his duties as the seventh head of the sprawling, wooded school for girls in July, subject to the approval later this month of Madeira's governing corporation.

Harris had been the headmistress for three years at the prestigious school. Her reportedly rigid rein on the student body came to a startling end last March 10 when she was charged with the shooting death of Tarnower, her longtime lover, in the bedroom of his fashionable home in Westchester County, N.Y.

In her trial now under way in White Plains, N. Y., Harris, 57, is accused of shooting the 69-year-old bachelor doctor because she was in a jealous rage over his affair with another woman, his nurse. The defense contends that a despondent Harris drove to Tarnower's home intent on killing herself and that the doctor was fatally wounded in a struggle for the gun.

The shock of Harris' arrest shattered the quiet of Madeira and stunned its students, faculty and alumnae. After the rush of attention from the media, the school began a methodical search for her replacement.

"I don't think there ever was a time when the operation of the school was disrupted," Karl Wolfe, director of development at Madeira, said yesterday. "Nothing is different, and our applicants are holding steady."

This year, Wolf reported, the school has admitted 335 day and boarding students, its largest enrollment ever. He said the school enrolls one out of five applicants, who pay tuition ranging from $4,200 to $7,000.

The search for a new administrator, according to Wolf, fell to a 10-member committee that employed the school's "usual recruitment and through screening" process. Working with nearly 100 written resumes, the committee checked references "on those that looked good" and invited a select group to the Madeira campus for further interviews. Members of the search committee visited the homes and schools of the most likely prospects and the finalists in the group were invited back to Madeira for more interviews with alumni, students and faculty.

"We were really looking for the best qualified, not for a man or woman," Wolf said. "He was the best."

Saltzman, in his early 40's, is a graduate of St. Albans School for Boys in Washington, received his bachelor's degree in art and teaching from the Harvard School of Education. He has teaching and administrative experience at a number of schools, including St. Albans, the Athenian School and Hannah More Academy. He is currently headmaster of the Metairie Park Country Day School in a suburb of New Orleans.

The Madeira School would not disclose what it will pay Saltzman, the father of two. Harris was said to be earning at least $22,000 at the time of her arrest.