The etymology of the name is unclear, although Ferdinand Justi proposes that Walagaš, the first form of the name, is a compound of words "strength" (varəda), and "handsome" (gaš or geš in Modern Persian).

[5] Vologases IV's forces seized a statue of Heracles, the patron god of the Characenian royalty.

[1][7] Vologases IV invaded Armenia and replaced its Roman client king Sohaemus with his own son Pacorus.

[7] Although the Roman–Parthian War of 161–166 started auspiciously for the Parthians, after the Romans recovered from the first shock and setbacks, they counterattacked, restored Sohaemus to the Armenian throne in 163.

[7] The chronicles do not report unrest or rebellions following the Parthian defeat, which the modern historian Michael Sommer refers to as a "disastrous military setback."

[15] However, due to its now higher strategic importance, Vologases IV elevated the titulature of the ruling Hatran family to that of king, and also allowed them certain ceremonies and traditional ritual oaths.

[8][17] The end of Vologases IV's reign was marred by the revolt of Osroes II in 190, who minted coins of himself at Ecbatana in Media.

[21] On some of the reverse of Vologases IV's bronze coins, an eagle is depicted, which is associated with the khvarenah, i.e. kingly glory.