The phrase "a longstanding trustee" is correct and usable in written English.
It can be used to describe someone who has held the position of trustee for a significant period of time, indicating their experience and commitment.
Example: "As a longstanding trustee of the organization, she has played a crucial role in its development and success."
Alternatives: "an established trustee" or "a veteran trustee".
A longstanding trustee and more recently honorary board member, Ruth served as chair of the agency's Jewish Conciliation Board.
As the Valedictorian of his Brooklyn Law School class; as a successful trial lawyer; as a longstanding trustee of the Village of Ocean Beach on Fire Island; and as a loving father, grandfather, great-grandfather and friend, Bill Wingate was a bright, caring, and extraordinary man.
The Jewish Board of Family and Children's Services acknowledges with great sadness the death of Judith Youngwood, an extremely dedicated and longstanding trustee.
Among his many charitable activities, Nelson generously carried on the commitment of his beloved wife Diana to the work of the Youth Counseling League, which she served as president and longstanding trustee.
"Opening Gramercy Park to the public for caroling on Christmas Eve is a longstanding, cherished tradition," said Arlene Harrison, a park trustee who is the founding president of the Gramercy Park Block Association and is known as the Mayor of Gramercy Park.
"The decision by the RDA UK board to place the UK company into an orderly insolvency process follows the recent decision by the UK Pensions Regulator that it would not support an agreement already reached between RDA UK, the trustees of its pension plan and the UK Pension Protection Fund PPFF) to settle a longstanding pension plan liability," RDA said.
Adidas is a longstanding partner.
"It's a longstanding belief".
This is, of course, a longstanding position.
He admitted to a longstanding drug problem.
Storytelling is a longstanding tradition among officers.
