After studying philosophy and theology for seven years in the German College in Rome, he obtained doctorates in both in 1576 and was ordained a Catholic priest.
Pope Gregory XIII gave Gibbons a canonry in the cathedral of the Archdiocese of Cologne, which was then located in Bonn, Germany.
Among Gibbon's literary works is Concertatio Ecclesiæ Catholicæ in Anglica, adversus Calvino-Papistas et Puritanos (Trier, 1583).
The work was republished on a larger scale in 1588 and 1594, by John Bridgewater, who numbered among his assistants Cardinal Allen and Humphrey Ely.
Bridgewater also edited (see, however, Dictionary of National Biography, s. v.) a posthumous work of Gibbons entitled Confutatio virulentæ disputationis theologicæ in qua Georgius Sohn, Professor Academiæ Heidelburgensis, conatus est docere Pontificum Romanum esse Antichristum a prophgetis et apostolis prædictum (Trier, 1589), in which he dealt with the Calvinist attacks on the papacy.