McCubbin, 61, signed a new, three-year contract with Kamehameha on Feb. 1 but suddenly resigned on Friday. He said in an interview today that he resigned to spend more time with his grandchildren and looked to possibly return to teaching at the university level.

"I really am looking at my health," he said. "I have a son in the Middle East and family considerations."

However, a person familiar with the situation said the trustees for months had been investigating a complaint of an inappropriate relationship between McCubbin and a female employee. The person asked not to be identified because of the sensitivity of the situation and the fact the trustees did not plan to talk publicly about the allegation.

McCubbin said today he was unaware of any allegations that he had an inappropriate relationship with anyone at Kamehameha. He said he spoke with trustees over the weekend, "and the question was whether I had moved the organization in the last three years, and whether I was challenged."

"What we have accomplished in the last three years is really quite significant," McCubbin said.

The Kamehameha trustees issued a statement today confirming McCubbin's resignation but the statement did not give a reason for his departure.

"As a personnel matter, it is not in the best interest of this institution to discuss the details of Dr. McCubbin's departure," the statement said. "What is best for Kamehameha has always guided us and will continue to guide us. This includes our decision to accept Dr. McCubbin's resignation."

The trustees selected Colleen Wong, vice president for legal affairs, to serve as acting CEO while they search for a replacement.

"We affirm the CEO governance structure and we are committed to keeping the CEO management structure in place," the trustees said in their statement. "We plan to have a new CEO in place within six months."

Trustees Constance Lau and Doug Ing met with state Attorney General Mark Bennett and deputy attorney general Hugh Jones this morning to brief them about McCubbin's resignation. The attorney general's office has oversight responsibilities for charitable trusts, such as Kamehameha Schools.

"At this point, it does not look like the attorney general's going to get involved in this situation," Jones said.

McCubbin is a 1959 Kamehameha alumnus who came to Kamehameha in 2000 after a career at the University of Wisconsin. He is married to Marilyn Ann McCubbin, a professor of nursing. They have three grown children.

The institution was founded in 1887 at the behest of Princess Bernice Pauahi Bishop and has grown into a $6 billion trust that is Hawai'i's largest private landowner and a major player on Wall Street.

Before McCubbin took over the top job at Kamehameha, the schools suffered through years of scandals and state and federal investigations that ultimately determined that the nonprofit institution was improperly managing its money and that some of the trustees had used their positions for financial and political gain. Trustees were also criticized for interfering with everything from admissions to curriculum and for refusing to delegate the trust's financial operations to professional money managers.

The five trustees were ousted in a series of legal maneuvers in 1999 and were replaced by a new board, which determined that it was better to have an executive in day-to-day operational control of the far-flung institution.

In a short time, McCubbin won praise for his vision and professionalism and also some criticism for allowing a non-Hawaiian student into the system on Maui.

"He got the system working and the school back on the right track," said Roy Benham, a member of Kamehameha's board of advisers.

Benham said he was not concerned that the school would revert to the problems that surrounded the trustees.

"I have confidence in the second-in-commands, that they will continue to function until the replacement is made," Benham said. "The trustees have the situation well in hand. They know there's no need for them to step in and take over. Their primary mission now is to touch more Native Hawaiian children and I'm confident that will keep going."

Unlike Benham, Beadie Kanahele Dawson said she is "very concerned" about the future direction of Kamehameha without McCubbin.

"I think that he was a substantial key to the rehabilitation of the estate and the school," said Dawson, an attorney who represented a group of parents, teachers and students that pushed for the removal of the former trustees.

Over the past few months, Dawson said she had heard "all kinds of rumblings in the background" about McCubbin.

"But I have the greatest admiration for him," Dawson said. "He's really an education professional's professional. I don't know immediately what it is, but I strongly suspect that he has been made an offer that he can't refuse. In Hawai'i this often happens when there's a good person. It's not unusual for people to, put it crudely, raid the treasure."

For now, McCubbin said his immediate plans include attending his daughter's graduation in Wisconsin, where she is earning a doctorate degree.

"Then I want to reconnect with my grandchildren, who feel I've been preoccupied with Kamehameha Schools, and rightfully so," McCubbin said.

Perhaps he will return to teaching, but not at Kamehameha.