The Byzantine general who reconquered Italy and North Africa under Justinian I was Belisarius. He was one of the Eastern Roman Empire’s most successful commanders and a central figure in Justinian’s attempt to restore former Roman territories.
Belisarius first defeated the Vandals in North Africa. In 533–534, he led a relatively small Byzantine expedition that captured Carthage and destroyed the Vandal kingdom. He then commanded the opening stages of the Gothic War in Italy, taking Rome in 536 and Ravenna in 540. The Italian campaign became far more difficult than the African conquest because the Ostrogoths recovered and resisted for years.
Belisarius did not complete every Byzantine victory in Italy; Narses later finished the conquest in 552–553. John Troglita fought in North Africa after Belisarius, while Mundus served in the Balkans. Thus, Belisarius is the canonical answer for Justinian’s famous reconquests, especially the initial campaigns in both regions.