The patient Ershad Chakma, 35, is a readymade garment worker. He returned to his native Kamukkachhara village in the upazila with his family from Narayanganj on April 18, said Civil Surgeon Dr Nupur Kanti Das.
"He's the first confirmed case in the district," Das said.
Chattogram Medical College Hospital tested his sample and confirmed his infection, the civil surgeon said.
The youth has been kept in institutional quarantine at a local primary school since his return, she added.
Local administration has put the school under lockdown, the doctor said.
Meanwhile, the health authorities announced the death of eight coronavirus patients and 641 new cases in the last 24 hours. So far, the country has confirmed 7,103 cases and 163 deaths.
Coronavirus, first reported in China, has infected more than three million people around the world and killed over 217,000.
Aslo read: Coronavirus cases in Bangladesh top 7,000; eight 8 more die
There is no vaccine for coronavirus yet.
The World Health Organisation (WHO) declared coronavirus crisis a pandemic on March 11.