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 Wisconsin, a trustee is responsible for managing a trust in accordance with the terms set forth by the grantor and the state's trust laws. The trustee's role includes the prudent management of trust assets, ensuring that the trust's objectives are met, and acting in the best interests of the beneficiaries. Wisconsin Statutes Chapter 701 governs trusts within the state, outlining the duties and powers of trustees, as well as the rights of beneficiaries. Trustees in Wisconsin are held to a fiduciary standard, meaning they must act with the utmost good faith, loyalty, and care in managing the trust. This includes avoiding conflicts of interest and not using the trust assets for personal gain. If a trustee is unable to 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 duties.