A powerful vampire, Alucard works with the Hellsing Organization against other vampires and evil forces. He has a range of supernatural techniques including enhanced strength, the ability to change shape, hypnotism, powerful regeneration, and others. He fights with ferocity and often extreme cruelty, rarely killing until his target has been disabled and humiliated, while frequently allowing enemies more than one chance to kill him. According to Volume 8 of the manga, he is Count Dracula. Soon after the events presented in Bram Stoker's book, Van Helsing gains control of Dracula, renaming himself Alucard (Dracula spelled backward), and leaves him as a servant of the Hellsing family. The manga takes place over a hundred years later, when the Hellsing organization is forced to fight remnants of a WWII Nazi organization.

He typically dresses in a distinctive Victorian and western fashion, with a charcoal suit, leather riding boots, a red cravat, and a long red duster (which resembles what Van Hellsing wore when he killed Alucard in the second OVA episode). He also wears a red fedora with a wide, floppy brim and a pair of circular, wire-framed sunglasses. However, this form seems to be a part of his being as he can change it at will.

Volume 8 presents flashbacks of when he was human. Dracula starts his career by fighting the Ottomans, believing that God does not reward prayer, but instead wants mortals to show their faith visibly. However, when his army is defeated and he is about to be executed, Vlad gives up on God, thinking that God deserted him and so turns his back to God in turn. It is not explicitly shown or stated how he became a vampire, but in one scene he drinks blood from the floor in front of an executioner.

The series mentions the events of Bram Stoker's Dracula, but deviates at the point of Dracula's defeat. In Hellsing, he was staked in the heart but not destroyed. It is unknown if he was forced into servitude or was willing, but he became a servant of the Van Helsing family. He, along with a young Walter C. Dornez, were sent to Warsaw, Poland to stop Millennium's vampire production program. Integra's father eventually imprisoned Alucard in a dungeon in the Hellsing manor, as he believed the vampire was too powerful to be used frequently After 20 years of imprisonment, Integra's blood awakened and resuscitated Alucard. He rescued Integra from her traitorous uncle and became her servant.