He had just beat out three other candidates for a coveted job and received a $24,000 raise to boot, but John A. Murphy did not look like a happy man. Indeed, the celebrity school superintendent from Prince George's County sounded more resigned than resolute as he explained last week why he had accepted the top education post in Charlotte, N.C.

Murphy noted he would be leaving Prince George's "with a great deal of sadness," but said "political realities" were forcing him to do so. Chief among them, he said, was the refusal last year of the county's representatives in the Maryland legislature to give him a 10-year contract extension.

"I made a commitment to finish my career in Prince George's County, but . . . commitments are two-party agreements," the 55-year-old Murphy said. "I couldn't put myself in the precarious position of promising to stay for 10 or 15 years, but make that subject to the whims of different political people who might be my bosses. I had to have a contract."

That job security, rather than his own need for a change, would prove to be the catalyst behind Murphy's departure has struck many observers here as terribly ironic.

After all, here is an educator who, in 1985, challenged the school board to fire him if he was unable to raise test scores of elementary school pupils by 20 points in four years -- and then raised them. At the same time, support for Murphy remained strong -- from the school board, County Executive Parris N. Glendening, prominent business leaders and many in the neighborhood schools.

Murphy's departure comes after a yearlong on-again, off-again job hunt that, it appeared yesterday, may not be over. Although the Charlotte-Mecklenburg School Board announced it had hired Murphy, he flew on Friday to Kansas City, Mo., where he is one of two finalists for the school superintendent's post. Murphy said he showed up for the interview as a courtesy because it had been arranged before the job offer from Charlotte came through.

"My total intention is to take the Charlotte offer, and nothing has changed that," he said. But he noted he has not yet signed a contract with the Charlotte board, and that until that occurs, "who knows what I'll be doing tomorrow."

The Kansas City board has discussed providing a salary that would be close to double the $120,000 he makes now; Charlotte has offered a first-year salary of $144,000.

The record of Murphy's nearly seven-year tenure in Prince George's is replete with accomplishments and accolades. In addition to making good on his promise to boost test scores, he narrowed the achievement gap between black and white students.

In 1988, the county's magnet program, a tool to desegregate schools, was commended by President Reagan. Two years ago, Murphy was part of a hand-picked delegation that Jesse L. Jackson selected to press the White House for the funds to begin a regional anti-drug effort. Late last year, he was named in one educational book as one of "12 educators in the nation who has made a difference."

As the countdown on Murphy's tenure began last week, his supporters were quick to point to other ways in which he had made an imprint on a school system that was plagued by a poor image, inadequate funding and low employee morale when he took over in mid-1984.

Murphy, then superintendent of a well-to-do district in Illinois, was hired on a 5 to 4 vote of the Prince George's school board.

Catherine M. Burch, a board member for 10 years and current chairman, said one of Murphy's greatest contributions was enlisting the county's business community, which contributed hundreds of thousands of dollars for a prime-time advertising campaign promoting the schools, funded numerous pilot projects and adopted individual schools.

In return, Murphy started a program two years ago giving employers who hired Prince George's graduates guarantees, promising that if the employees were not satisfactory, they could be returned to the school system for additional training free of charge.

Burch recalled that before Murphy's arrival, she went to the president of the Chamber of Commerce and told him of her dream that he go to a public hearing and support the school budget. According to Burch, "He said, 'That is not a dream, Cathy, it's a nightmare . . . . ' Dr. Murphy somehow persuaded them {business leaders} that it would be in their best interests to support us."

Murphy also quickly gained a reputation as an innovative administrator. Eugene L. Colgan, principal at Surrattsville High School in Clinton for the last decade, said Murphy's chief legacy is that "he allowed people to be creative and to question whether the standard instructional methods were effective or not."

According to Colgan, Murphy put the onus for student achievement on principals and teachers. While concepts such as school-based management, a deemphasis on student tracking and teacher lectures and the importance of computers and other technology in the classroom have now gained wide acceptance, they were considered somewhat radical when Murphy first proposed them, Colgan said.

Several observers said last week that Murphy's extended honeymoon in Prince George's probably would have continued if not for the political blunder that surrounded the effort to prevent him from accepting a job in Florida a year ago.

At Glendening's urging, the board drafted an agreement that would have extended Murphy's remaining 28-month contract by 10 years and boosted his salary. Murphy accepted the offer, agreeing to shun other job offers. He said the extension was crucial because he didn't want to gamble on the outcome of next year's school board elections, in which six of the nine members face primaries.

But the deal, which needed the approval of Prince George's legislative leaders, sparked a public outcry. Parents attacked a $2 million contract at a time when schools lacked such basics as textbooks and copying machines. Some black parents and community leaders said the length of the contract would prevent the hiring any time soon of a black superintendent, a prospect some found troubling in a county whose student population is expected to be 70 percent black by the turn of the century.

The uproar caused the county's lawmakers in Annapolis to denounce the agreement, and Murphy pulled out of the deal, decrying the county's "racial politics and political gamesmanship." The ensuing debate gave rise to questions about Murphy's job performance.

Murphy critics point out that even with the improvements in national and state functional test scores across the board, the average scores on the Scholastic Aptitude Tests taken by college-bound students have not increased as much. They also note that it is not only Murphy's magic touch that accounts for the improved academic climate in the county, but also the rise of a strong black middle class that demands educational excellence from its children.

Even though Murphy has been widely credited for helping to increase the number of minority students going to college and to decrease the number being suspended from school, he also has been blamed in some quarters for the dismal statistics surrounding the achievement of the county's black male students. The popular magnet program has also been haunted by criticism, not unique to Prince George's, that it has engendered a new form of school segregation.

"While we did not think there had not been significant progress, there were also significant problems. We had not yet run the Super Bowl. Even if you win the Super Bowl, you don't get a 10-year, no-cut contract," said state Sen. Albert R. Wynn Jr. (D-Prince George's), one of the lawmakers Murphy holds responsible for his decision to leave Prince George's.

Those close to Murphy say that the contract dispute left him wondering how long he would have the political support to get the job done.

Susan Pimentel, one of Murphy's special assistants, said, "I think his sense was . . . that we were going to have to make another big push to get things to the next level, and that unless the community could really rally, it was probably best that he move on."