In 1867 Pope Pius IX appointed him as the Titular Bishop of Calydon.
Grech Delicata Testaferrata was consecrated by Cardinal Lodovico Altieri on July 14, 1867, in the chapel of Villa Lante al Gianicolo in Rome.
He succeeded Paolo Micallef as administrator who was later appointed as Archbishop of Pisa in 1871.
The see of Gozo was vacant for two years after the death of its bishop Michael Franciscus Buttigieg.
He spent the remaining seven years as the Bishop of Gozo until 31 December 1876 when he died in Valletta.