Bishop Sullivan serves on the boards of  the Churches' Center for Theology and Public Policy in Washington, D.C.; the Virginia Interfaith Center for Public Policy and numerous diocesan boards.  He has been on the boards of the National Catholic Office for Persons with Disabilities; the Christian Children's Fund based in Richmond; the Catholic Committee of Appalachia and on the Administrative Board of the National Conference of Catholic Bishops.  Likewise, he has served as the Bishop-President of Pax Christi USA, the national Catholic peace movement. 

Bishop's Coat of Arms: The coat of arms of Bishop Sullivan contains the lions and the stag from the Sullivan coat of arms of Ireland, but is differenced to make the coat of arms personal. The Trefoil between the Sullivan lions is taken from the coat of arms of Bishop Russell, whom Bishop Sullivan assisted as Auxiliary. The group of trees identifies the Vanderloo family of the Bishop's Mother. The dexter implement contains the arms of the See.

Motto: "To Unite All in Christ". The motto is derived from the prayer of Jesus Christ for unity at the Last Supper: "That all may be one, even as thou, Father, in me and I in thee; that they may also be one in us, that the world may believe that you have sent me" (John 17:21).