Yongsan police station chief Lee Im-jae is the first senior police official to be convicted over the crush, which led to 159 deaths nearly two years ago.
Lee had failed to prepare for a mass Halloween gathering whose dangers he should have foreseen, thus creating the conditions for the Itaewon tragedy, the Seoul Western District Court said in a statement.
The Itaewon deaths shocked a nation still scarred by the 2014 sinking of a ferry, the Sewol, that killed 304 people including 250 children on a school trip.
Two other former Yongsan police officials were handed a two-year jail term and a one-year prison term suspended for two years, respectively.
The court ruled the crowd crush was a "man-made disaster" that could have either been prevented or the impact substantially reduced if the accused had fulfilled their duties.
Speaking to the Yonhap news agency before the ruling on Monday, Lee's lawyer said it was "excessively harsh" to expect his client to have prepared for something that nobody could have predicted.
The deadly stampede was a "man-made disaster" that could have been prevented, the court ruled. (AP PHOTO)
Park Hee-young, the Yongsan district office chief, along with three other district officials were found not guilty of failing to adequately respond to the crush.
The court said they had not been directly responsible for crowd control.
At a news conference ahead of the ruling, relatives of the victims had called for both Lee and Park to be held accountable.
Since the tragedy, relatives have called for the punishment of senior officials, including Minister of the Interior and Safety Lee Sang-min.
The constitutional court ruled against a parliamentary vote to impeach the minister in 2024.
Prosecutors had sought seven-year jail terms for both Park and Lee, according to media.
Earlier in 2024, parliament passed a bill backed by the ruling and opposition parties to launch a fresh investigation into the Halloween crush.