A trustee is a person or entity designated by a person who creates a trust (grantor, settlor, or trustor) to manage and administer the trust for the benefit of the named beneficiary or beneficiaries. The trustee of a trust created for estate planning purposes is often the grantor, settlor, or trustor who created and funded the trust.

A trust agreement may designate one or more successor trustees who will become the trustee if the previous trustee dies, is unable to continue to serve as trustee, resigns as trustee, or is removed by court order following a lawsuit filed by the beneficiary or beneficiaries of the trust.

A trustee has a fiduciary duty to the beneficiary or beneficiaries of the trust. A fiduciary duty includes the highest duty of care (performance of duties under the terms of the trust agreement) and of loyalty (avoiding conflicts of interest) recognized in law.

In North Dakota, a trustee is responsible for managing a trust in accordance with the terms set forth by the grantor and in the best interests of the beneficiaries. The trustee's role includes a fiduciary duty, which is the highest standard of care in managing the trust's assets and avoiding conflicts of interest. This duty is established under North Dakota Century Code (NDCC) Title 59, which governs trusts, and includes the Uniform Trust Code adopted by the state. The trustee must act in good faith and in accordance with the terms and purposes of the trust and the interests of the beneficiaries. If the original trustee can no longer serve due to death, incapacity, resignation, or removal by the court, a successor trustee, as designated in the trust agreement, will take over the management of the trust. Beneficiaries have the right to take legal action if they believe the trustee has breached their fiduciary duty.