- "The nature does not have the knowledge of the philosophical thought, Geralt of Rivia. Us, mages, can and have to do whatever we can to comprehend its gentle threads...And then it shows us its power..."
As an infant he was abandoned by his parents. He was found and raised by druids and only became a mage as an adult. During his stay at the druids, a mage visited them. He offered to take Vilgefortz and teach him, feeling his magical energy. Vilgefortz refused his offer. Later he left the druids, and traveled over the world. He served as a mercenary, and later as a spy. He himsellf recalled being ashamed of the things he has done, including robbing people and killing. At the end, he was running to the other end of the world from the executioner's axe. There, he met a woman. He had a short romance with her, yet later when she left him, he joined the mages.
In fact, he was not only incredibly ambitious and power-hungry, but also secretly in league with Emhyr var Emreis, the Emperor of Nilfgaard. This had begun many years before the wars, while Emhyr was still hiding under the alias of Duny. Vilgefortz's thirst for unlimited power brought him to the conclusion that he needed Ciri's, Duny's daughter's, blood in order to claim her powers because she is a descendant of Lara Dorren. Using intrigues and his genial intellect, he helped Emhyr rise to the throne. In exchange, Emhyr promised him the North, once it was taken over.
During the Thanned ball, he accompanied Francesca Findabair. Later, he talked with Geralt, in a rather philosophical manner.
On Thanedd Island, he (among others) was accused of treason and put in dimeritium shackles. However, due to actions of Tissaia de Vries (who was acting only in a manner she considered fair and impartial) he broke free and tried to capture Ciri. During his way, he encountered Geralt. Vilgefortz didn't use magic, instead he attacked Geralt with a staff. Vilgefortz easily defeated Geralt, leaving him alive for the beating to be taken as a 'lecture'. He continued tracing Ciri but she fled through the portal in Tor Lara, then the portal exploded and caused him serious wound on his face (he lost one eye). Afterwards he hid in his castle, continuing his schemes to find and capture the girl, including hiring the bountyhunter Leo Bonhart. He planned to use Ciri's blood and use it on himself. During his search, the spy Dijkistra encountered the horrible experimenrs Vilgefortz has done on girls.
Later, he imprisoned Yennefer and tortured her to retrieve the location of Geralt and Ciri, He then applied dimeritium cuffs to Yennefer to prevent her from escaping and locked her in a cell.
During the attack at Castle Stygga he met and fought Geralt and Yennefer. Yennefer was no match for his magical abilities, being defeated easily by him. Then the vampire Regis attacked, scratching Vilgefortz just under his not working eye. Vilgefortz ignited the vampire, and engaged in a melee duel with Geralt. Vilgefortz was winning once again, until Geralt gained the upper hand thanks to the shock Vilgefortz suffered when the witcher dodged his attack with a high-level illusion (This illusion was not his doing, it was thanks to an amulet he received). That was the end of Vilgefortz.
- In the Prologue, Lambert says that Geralt has "killed a few (sorcerers) in (his) time", possibly alluding, amongst others, to Vilgefortz.
- Later in the Prologue, if Geralt fought Savolla, he can ask Triss what she thought of the unfamiliar mage. Her reply includes the line "we might soon be facing another Vilgefortz." When Geralt's reaction is merely "Who?", she tells him to forget about it.
- Zoltan also invokes the name of Vilgefortz during a conversation with Geralt in Chapter II.
- Elder Blood is an in-game book attributed to him.
- At the end of Chapter V Azar Javed says:"This time you pissed into a tornado". This was a quote from Vilgefortz.
In the main quest The Sunstone, Geralt and Philippa discuss about Vilgefortz's experiments to regain his lost eye, with Philippa cutting the Witcher off believing he was trying to imply a similarity between the two.