Dr. Cullum is one of the founding faculty members of Northeastern Seminary at Roberts Wesleyan College.

Areas of special interest include Reformation theology and history, Wesley and the Methodist tradition, liturgy and liturgical theology, and nineteenth and twentieth-century American religion.

Dr. Cullum participates in the North American Academy of Liturgy, the Wesleyan Theological Society, and the American Academy of Religion.

His teaching ministry seeks to blend the academic and the practical, with a focus on strengthening the local church along biblical and classical lines.