Pope Pius V had him sent to Paris where for two years he studied the Church Fathers and the Councils, Greek and Hebrew.
At the age of twenty-three he was sent to Rome, where his sermons attracted much attention. Returning to Italy he preached during thirteen years in the principal towns. He converted many Calvinists in France and Savoy.
At Naples there was collected, through one of his sermons, enough money to build a hospital for incurables.
He also assisted in the construction of the Italian church of Antwerp, and of the Franciscan buildings at Genoa, Venice, Milan, and Turin. During his lifetime Panigarola was known for his prodigious memory.
Through diligent practice of the memory palace system, he had allegedly accumulated a mental collection of more than one hundred thousand memory images. In 1579 Panigarola attended, as custos of his province, the general chapter at Paris.
Finally in 1586 Pope Sixtus V appointed him titular Bishop and Coadjutor of Ferrara, whence in 1587 he was transferred to the See of Asti.
Shortly after he was sent to France as assistant to the papal legate, Cardinal Henry Cajetan.