He was Bishop of Cuenca (1272) and Burgos (1275) and then Archbishop of Toledo (1280), the first official Primate of Spain (1285) and finally Cardinal-Bishop of Albano (1298) in the Roman Curia.
Under Sancho IV, Gonzalo was "great chancellor in all our realms" (chanceller mayor en todos nuestros regnos) and Ferrand Martínez his scribe, but with the king's death in 1295 the archbishop's influence decreased.
[5] Gonzalo was one of those who opposed the assumption of the tutorship of the young king, Ferdinand IV, by his uncle, Henry the Senator, regarding the latter as "a great disturber" (un gran bolliciador).
He died not long after in Rome, where he was buried in a "very nobly worked" (muy noblemente obrada) sarcophagus in the church of Santa Maria Maggiore, “near the chapel of presepe domini, where Saint Jerome lies buried.”[6] In the year 1300, in keeping with a promise he had made to the cardinal some years earlier, Ferrand Martínez went to Rome to fetch his body for burial in the cathedral of Toledo, in the front of the chapel of Santa María la Blanca.
The story of Gonzalo's relics is told in the prologue of the near-contemporary chivalric novel Libro del caballero Zifar, possibly written by Ferrand Martínez.