Belasco was granted most of his power by the Elder God he serves. Among other feats, he can hurl bolts of mystical force, mesmerize victims, transform people into animals, and raise the dead under certain circumstances. His long studies of the black arts have given him an encyclopedic knowledge of spells that he can use. The Elder Gods also granted Belasco immortality and apparently invulnerability as well. Possibly the only means of killing him is his own sword, which was forged by the Elder Gods and was used to sever his right arm.
Belasco's powers are somehow linked to those of Magik (Illyana Rasputin). When they fought their climactic battle in Limbo, Magik took on a demonic form while simultaneously Belasco reverted to human form, losing most of his power and his invulnerability in the process. It is not known whether Belasco would lose his demonic form and powers whenever Magik takes on her demonic form. Belasco carries a sword forged by the Elder Gods which is capable of harming Belasco himself.
Belasco has considerable knowledge of much of the technology that the pre-cataclysmic Atlanteans found in Pangea.
Belasco was formerly master of the demonic dimension called Limbo. Time does not pass in a physical sense in Belasco's Limbo, and Magik aged seven years while she was there. However, one might spend years in Belasco's Limbo while no more than moments pass on Earth, due to the unknown temporal laws of the former place. The matter within Belasco's Limbo can be shaped and transformed by the thoughts and emotions of the sorcerer who is its master. Belasco's Limbo is populated by demons who serve its master.