Haitch Macklin, 38, was handed a jail term of 20 months in April after thousands of indecent photos and videos of children, including babies, being subjected to sexual abuse were found on his devices.
But at a hearing on Thursday, his sentence was increased to four years, after three Court of Appeal judges ruled that the original term did not "reflect the gravity of the offending".
He sold access to his catalogue of videos and photos via an encrypted messaging app for £10 a month, advertising the service in an online chatroom where he used the name "UK perv", the court heard.
The court also heard that at one point, when contacted by a covert international investigator who asked what type of images he had, Macklin replied with instructions on how to pay and indicated that there were "babies, girls and boys under 10".
Macklin, of New Devonshire Square, Salford, Greater Manchester, pleaded guilty in December to two counts of showing indecent images of children and three counts of making indecent images of children, including more than 600 classed as category A - the most serious.
Lady Justice Macur said: "We come to the sure conclusion that we cannot accept that the sentence reflects the gravity of the offending in this case, and that it does not do so by some margin."
After he was jailed in April, the National Crime Agency (NCA), which said Macklin worked part-time as a DJ known as DJ Spook, said officers had noted that the material he sold access to was "some of the most horrific and disturbing content they've ever seen in many years investigating child sexual abuse".
The NCA said Macklin's collection included sexual torture videos of babies and toddlers, and that he had told of his desire to acquire "snuff" films showing real-life killings, and spoken about wanting to murder someone and film it.
Macklin, who was born David Bradley, was previously known as Haitch Bradley, the NCA said.
Macklin had first come to the authorities' attention in April 2018 when investigators traced an IP address to him after it was used to post an indecent comment in an online chat session.
His sentence was referred to the Court of Appeal by Solicitor General Michael Ellis under the unduly lenient sentencing scheme.
In a statement after the hearing, Mr Ellis said: "The extent of Haitch Macklin's involvement in this grossly abhorrent distribution of child pornography is sickening.
"I am pleased that the court has found his sentence to be unduly lenient and decided to increase it."