The first Catholic mission in Texas, then part of the Spanish Empire, was San Francisco de los Tejas.

As bishop, he created a consultation process that included clergy, members of religious orders, and lay people to assist in diocese planning.

[4] In 1989, Pope John Paul II named Grahmann as coadjutor bishop of the Diocese of Dallas-Fort Worth.

Replacing Grahmann in Victoria in Texas was Reverend David Fellhauer from the same diocese, named by the pope in 1990.

On January 21, 2019, Bishop Cahill named three diocesan priests with credible accusations of sexual abuse of minors.