After 13 hours' deliberation, a jury found 28-year-old Darren Vickers, from Gorton, Greater Manchester guilty of murdering Jamie Lavis on 5 May 1997.
The boy's dismembered remains were found on a golf course in Stockport, Greater Manchester, five months after his disappearance.
No cause of death was ascertained and there was no forensic science evidence to link Vickers to the killing.
Yesterday at Manchester Crown Court, Mr Justice Forbes told Vickers his crimes were "truly wicked".
He said: "Jamie's brief life was cruelly and prematurely brought to an end because he had the tragic misfortune of boarding your bus. You manipulated the family, the press and the police. You lied and lied and lied again."
During the seven-week trial, the court had heard how Jamie, from Ashton- under-Lyme, had boarded Vickers' 219 bus in nearby Openshaw after he became bored staying at home on a bank holiday.
Vickers allowed him to change gear and count change. He also gave him money to buy drinks, ensuring that the child stayed on his bus all day.
Passengers saw Vickers ruffle the boy's hair, and another driver saw Jamie with his face pressed against the window of the driver's cabin. The court was told that, all along, Vickers was "grooming the boy for his own base motives".
When the day ended, Vickers drove the boy to Dukenfield, where he collected his car. Shortly afterwards, at an unknown location, he stripped and abused the boy, murdered him, dismembered the body and then concealed his remains. The boy's head and some of his limbs have never been found.
In a perverse twist, Vickers then ingratiated himself with the boy's family. During the high-profile search for Jamie, Vickers was filmed for TV news bulletins comforting the family and appealing for information.
Vickers used a radio scanner to listen for information on the search for Jamie and would turn up at reported sightings before the detectives.
He also claimed to have started a sexual relationship with the boy's mother, Karen Spooner - something she denied vehemently.
Brian Leveson QC, for the prosecution, told the court only two people really knew what had happened after Vickers lured the youngster into his car.
"Jamie Lavis isn't here to tell us, and his attacker hasn't told us yet," he said.
After yesterday's decision, Ms Spooner said she felt relieved. "I don't really want to say how I feel," she said. "I hate the sight of him. Jamie can rest in peace now. We have got what we wanted. I hope [Vickers] suffers like I have suffered with my family for the last two years."
Mr Justice Forbes praised Detective Superintendent Roy Rainford and his colleagues at Greater Manchester Police for their hard work on the case. He also thanked two children, Zoe and Ashley, who helped the police to catch Vickers, and awarded them pounds 150 each from public funds for their help.Reuse content