Few details are known about Hranislav prior to his capture by the Byzantines. Byzantine historian George Pachymeres describes him as a "warlike man, a Bulgarian by descent" and one of Ivaylo's officers and supporters. Historian Plamen Pavlov theorizes that Hranislav must have been an early follower of Ivaylo from the very outbreak of his uprising and thus one of his most trusted commanders. He believes Hranislav was granted the Byzantine loan-title of "megas primikerios" after Ivaylo was installed in the capital Tarnovo.