The 70-year-old cricketer-turned-politician was accused of misusing his premiership minister from 2018 to 2022 to buy and sell gifts in state possession that were received during visits abroad and worth more than 140 million Pakistani rupees ($635,000).
“Judge Humayun Dilawar announced that involvement in corrupt practices has been proven,” Pakistan TV said on Saturday.
The verdict includes a 100,000 rupees fine ($355) which, if not paid, could amount to a further six months in jail.
Khan’s lawyer Intezar Panjotha told the Reuters news agency police arrested Khan from his residence.
“We are filing a petition against the decision in high court,” Panjotha added.
In a video recorded before his arrest and posted on social media platform X, formerly known as Twitter, Khan called on his supporters to take to the streets in protest.
“I only have one request, one appeal for you. You must not sit quietly inside your homes. The struggle I am doing is not for my own self, it’s for my nation, for you. For the future of your children,” he said.
“If you don’t stand up for your rights, you will live lives of slaves and slaves don’t have a life,” he added.
His arrest and detention for several days in May over a separate case had sparked intense political turmoil and deadly clashes had erupted between Khan supporters and police.
There have been no reports of emerging protests in any of the major cities immediately after Saturday’s arrest. The opposition leader’s residence had been sealed off and that security forces were patrolling the area.
Protocol requires prime ministers to store the objects in the state’s safe house, while Khan is accused of having sold them at a profit.
The gifts allegedly included watches, perfumes, diamond jewellery and dinner sets.
Babar Awan, a member of the Pakistan Tehreek-e-Insaf (PTI) party and of Khan’s legal team, said the ruling was a “ridiculous verdict by a sham court”.
“Imran Khan was not given a fair trial, which according to country’s constitution is the right of every citizen,” Awan told Al Jazeera.
“We are going to appeal the verdict in high court under Pakistani laws and there is every likelihood of suspension of the verdict and early release of Imran Khan,” he added.
Khan was not present in court for the hearing. Over 150 cases were brought against him since he was ousted in April last year.
He has denied any wrongdoing, saying the charges are politically motivated.
Pakistani law does not provide for the possibility of holding trials in absentia, under which Khan was charged. Therefore, Awan said, there was “every likelihood of suspension of the verdict and early release of Imran Khan” following the appeal to the high court.
Senior PTI leader Asad Umar also criticised the ruling in a post on X.
“Today’s decision does not meet the basic principle of law and justice should be seen. This decision will not stand in the Supreme Court. And meaningful decisions about politicians are made in the hearts of the people, not in the courts,” he wrote.
Legal experts say a conviction in the case could end his chances of participating in national elections that have to be held before early November.