Former boy band member Ilhoon was sentenced to two years in prison and fined 133 million won (S$160,000) yesterday for purchasing and using marijuana on 161 occasions.
Seoul Central District Court senior judge Yang Cheol-han presided over the sentencing of the 26-year-old rapper and singer, whose real name is Jung Il-hoon, formerly of BtoB.
The judge also deemed it necessary to arrest Jung in court because he was considered a flight risk, according to a report on entertainment website Koreaboo.
The prosecution had previously asked for four years in prison for Jung's crimes, which came to light last year.
Jung had left the popular seven-member band in December.
He and seven other defendants were on trial for buying 826g of marijuana worth 133 million won and smoking it 161 times between July 5, 2016, and Jan 9, 2019.
According to entertainment portal Soompi, the seven other defendants received sentences of between 1½ and two years, or a suspended sentence.
His lawyers pleaded for leniency during the trial, saying their client had a difficult time as an idol.
"He worked in the entertainment industry at such a young age and tried to relieve the stress in the wrong way," they said.
The court said: "The defendants communicated through the Dark Web in order for their crimes to not be easily detected and used elaborate criminal methods, such as making transactions with the cryptocurrency Bitcoin."
Jung and another defendant, known only as Park, were named the leaders of the group by the court, which added: "The two defendants played leading roles and carried out the criminal acts the greatest number of times."