Born in Caserta, Alfonso was the fourth-in-line heir to the throne of Two Sicilies since the time of his birth. Ahead of him in line were his older half-brother Francis and older brothers Prince Louis, Count of Trani and Prince Alberto, Count of Castrogiovanni. On 12 July 1844, Alberto died, two months short of his fifth birthday and naturally childless which made Alfonso the third-in-line. On 22 May 1859, Ferdinand II died, making Francis the king. Francis had no children yet from his wife Duchess Maria Sophie in Bavaria. Louis became his heir presumptive and Alfonso the second-in-line heir to their half-brother.
The Two Sicilies were conquered by the Expedition of the Thousand under Giuseppe Garibaldi in 1861 leading to the end of the Kingdom of Two Sicilies. Garibaldi served the Kingdom of Sardinia which was in the process of Italian unification. The deposed Royal House survived with Francis still at its head, even though he was no longer King. On 8 June 1886, Louis died. His only daughter Princess Maria Teresa was not in line for the throne, because females were barred from succession. Louis' death made Alfonso the heir presumptive to Francis, who had survived his own daughter. On 27 December 1894, Francis II died, making Alfonso the head of the House of Bourbon-Two Sicilies. Alfonso later died at Cannes on May 26, 1934.
∞ Beatrice Bordessa, created Countess of Villa Colli, born into a bourgeois Italian family from Chester in the North of England.[3] This marriage produced no issue.