The current shield is the second used in the Diocese of Fond du Lac, adopted during the episcopate of Bishop William Brady. Shields evolved from the coat of arms historically used in the mid-twelfth century to identify allies and use has expanded over time. The design is to be a unique symbol. Many shields are in use by a variety of institutions and individuals. As with all shields, it is meant to convey a number of meanings.
The current diocesan shield is included in Heraldry in the Episcopal Church: How ecclesiastical coats of arms depict the history of the church (1993) by Eckford De Kay and published by Acorn Press.