Matthew Mason had previously admitted striking teenager Alex Rodda to death with a wrench in woods in Ashley, Cheshire, on 12 December 2019.
But he denied murder, claiming he had suffered a loss of control after being blackmailed by the schoolboy, paying him more than £2,000 to keep their sexual relationship secret.
However, a jury at Chester Crown Court on Monday, 25 January, found the farmer’s son guilty by majority verdict of the premeditated killing, with evidence showing Rodda had been struck at least 15 times.
The prosecution described it as a brutal attack on Rodda after he was lured to the remote spot.
Honorary Recorder of Chester Judge Steven Everett told the court that Mason, from Ollerton in Cheshire, had groomed Rodda, and set the minimum jail time at 28 years.
The judge told him: “This was a premeditated murder, carefully planned and, in my judgment, ruthlessly carried out showing no empathy for your victim and a callous disregard for his family and friends.
He added: “Although I accept Alex Rodda may very well have initiated contact with you in the latter half of 2019, I am sure that you not only responded but actively encouraged a sexual relationship.
“You groomed him. It was not your first sexual experience but it was his.
“While it is clear that Alex Rodda naively, as I see it, demanded money from you. It must be firmly kept in mind that this all came about because of your sexual offending and you chose to behave in that way.
“You made a firm and clear decision to kill Alex Rodda some time in early December 2019. This was not something on the spur of the moment. You were hoping you would kill him and hide his body to make it look as if he simply decided to disappear.
“You went about it with a ruthlessness which utterly beggars belief for any person, let alone someone in their teens.
The court had also been told that Mason had paid Rodda to stop the schoolboy from revealing their sexual relationship.
Jurors heard that Rodda, from Tabley, Cheshire, had contacted Mason’s girlfriend in November 2019.
Rodda told her that he and Mason had been exchanging flirty and explicit messages.
Mason denied this to his girlfriend and started to send Rodda money. By the time of the murder, Mason had sent more than £2,200 to the 15-year-old and had asked friends to borrow money, the court heard.
Giving evidence, Mason admitted having sex with Rodda but said he thought that it was wrong.
The killer, who was an agricultural engineering student, said he did not believe his friends would accept him if he was gay or bisexual.
After the attack, the court heard that Mason went to a friend’s house to clean himself up and then went on to spend the evening with friends at two different pubs.
He returned to the scene of the killing later in the evening, before being arrested the next day after Rodda’s body was found by refuse collectors.