He walked out of Kashimpur Central Jail-2 around 12:15pm Thursday, said Jail Superintendent Abdul Jalil.
"We have received the bail document around 9:30 am and released him after scrutiny," he said.
Kishore left the jail premises around 12 pm with his friends and relatives who were waiting outside to receive him.
He did not speak to the media.
The High Court granted six-month bail to Kishore on Wednesday.
Writer Mushtaq Ahmed, co-accused in the same case, died in jail on Feb 25. His bail was sought in an application before his death, along with Kishore’s.
Kishore was arrested with writer Mushtaq on charges of propagating disinformation against the government on social media in a case under the Digital Security Act.
The case was started against 11 people by Deputy Assistant Director Zahirul Islam of RAB-3 with Ramna Police Station.