Pope Paul IV confirmed his election on August 23, 1555, and he was ordained by Rudolf von und zu Frankenstein, Bishop of Speyer, in June 1557.

Daniel Brendel founded a college for the training of Jesuits at the University of Mainz in 1561.

During the imperial election held in Regensburg on October 27, 1575, Daniel Brendel voted for Rudolf, King of the Romans, whom Daniel Brendel later crowned Holy Roman Emperor in Regensburg in 1576.

Daniel Brendel expanded the size of the Archbishopric of Mainz by acquiring Rieneck (1559), Eppstein, and Königstein im Taunus (1581).

Daniel Brendel's head cook, Marx Rumpolt, published the famous cookbook Ein new Kochbuch in 1581.