The successor trustee is the person who assumes control of the trust after you, the initial trustee, die. The successor trustee makes sure that your estate is distributed among your beneficiaries according to the terms of the trust. Usually the successor trustee is someone that you know well and trust.
A trustee following the original or prior trustee, appointment provided for in the trust instrument.
The person (or institution) who takes over as trustee of a trust when the original trustee(s) have died, resigned, or become incapacitated.