Between 1936 and 1939, Bergonzoli was ordered by Benito Mussolini to Spain, forming part of the Corpo Truppe Volontarie, in support of General Francisco Franco and the military rebels during the Spanish Civil War, with Bergonzoli taking charge of the 4th Infantry Division Littorio.

For his performance in the capture of Santander during the northern campaign, he received an Italian decoration, the Gold Medal of Military Valour.

He was one of the architects of the so-called Pact of Santoña, by which the Italians accepted the agreed surrender of the Republican People's Army militants affiliated with the Basque Nationalist Party.

[citation needed] Bergonzoli was the commander of the Italian garrison in Bardia, which fell on 5 January 1941 following an assault by Commonwealth forces.

He left Tobruk before the town was captured by Commonwealth forces on 22 January, but on 7 February 1941 Bergonzoli, along with the remnants of the 10th Army, was taken prisoner by troops of the 6th Australian Division in the Battle of Beda Fomm.