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 New York, 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 is fiduciary, meaning they must act with a high degree of care and loyalty, and must avoid conflicts of interest. New York's Estates, Powers and Trusts Law (EPTL) provides the legal framework for the creation and administration of trusts, including the duties and powers of trustees. Successor trustees can be appointed in the trust agreement to take over if the original trustee can no longer serve. If a trustee fails to uphold their fiduciary duties, beneficiaries may seek legal recourse, which can include the trustee's removal through a court order. Trustees in New York must also comply with any relevant federal laws, such as those pertaining to taxation of trusts.