He participates in the Vandalic War and serves in North Africa as a regional military governor during the years 533–538, before being sent east to the wars with the Sassanid Persians.
As dux Mesopotamiae, Troglita distinguishes himself in several battles, and is noticed by agents of the Byzantine emperor, Justinian I (r. 527–565).
In summer 546, Justinian chooses John Troglita to assume overall command of Byzantine forces in Africa, where a succession of revolts by the indigenous Moorish tribes and within the imperial army itself has seriously reduced the Byzantine position.
Troglita quickly secures an initial victory in the winter of 546/547 against the Moors of Byzacena, but is defeated in summer 547 by the tribes of Tripolitania, and Africa is once again laid open to destructive raids.
Troglita reorganizes his army and secures the assistance of some tribal leaders, and confronts and decisively defeats the tribal coalition at the Fields of Cato in summer 548.
This victory spells the end of the Moorish revolt, and heralds an era of peace for Africa.
Troglita is also involved in the Gothic War, twice sending some of his troops to Italy to assist against the Ostrogoths.
John Troglita's exploits, especially against the Moors in Africa, are the subject of the last Latin epic poem of Antiquity, the Iohannis, seu de Bellis Libycis ("Tale of John, or On the Libyan War") of Flavius Cresconius Corippus, which is the main source on his life.
