Yoo, whose real name is Uhm Hong-sik, was accused of using propofol on 181 occasions between 2020 and 2022. The drugs were administered at professional clinics, under the guise of having cosmetic procedures done.
The prosecution had sought a four-year sentence for the "Hellbound" actor, but the Seoul Central District Court handed the 37-year-old a one-year jail term, Yonhap reported.
"He is deemed guilty of all his purchases for habitual drug use," the court stated in its ruling, according to Yonhap News TV.
The court said Yoo had committed the offences "in disregard of relevant regulations" and displayed a "lack of caution against drug substances".
A doctor who administered propofol to Yoo without a proper prescription was fined 40 million won ($30,000) last month.
Propofol, while primarily used as a surgical anaesthetic, is sometimes abused recreationally, often with the involvement of medical professionals who may be willing to provide it without a legitimate clinical need.
An overdose of the drug was cited as the cause of pop star Michael Jackson's death in 2009.
"I am sorry for having caused concern to many people," Yoo was quoted as saying in court by Yonhap.
Yoo rose to stardom in the South following his debut in 2003, starring in a range of television dramas and films across genres, and becoming one of the country's most recognisable actors.
This trial marks the latest drug scandal to hit South Korea.
In a similar incident, K-pop star G-Dragon faced allegations of drug use and was questioned by police, but the case was dropped in November due to insufficient evidence.
Actor Lee Sun-kyun, known for his role in the Oscar-winning film "Parasite", took his own life in December after being accused of illegal substance use, sparking public outrage over what many perceived as an excessive investigation by the police without substantial evidence.
Lee Jae-yong, then vice-chairman of Samsung Electronics, was convicted in 2021 of illegally using propofol and was fined 70 million won. He was found guilty of repeatedly receiving the anaesthetic at a plastic surgery clinic in Seoul on numerous occasions over several years.
