Mech Dara, who is known for exposing corruption and human trafficking, had been held in pre-trial detention since October 1, and faces up to two years in prison.
His arrest drew concern from rights groups and the US government.
In its October 1 decision, the Phnom Penh Municipal Court said Dara, who has worked for local and international media, had posted "provocative" and "false" messages and pictures about a rock quarry on a sacred mountain.
Dara spoke briefly to reporters outside the Kandal provincial jail before leaving in a vehicle.
He thanked civil society groups and embassies for helping to facilitate his release.
"I am very thankful to everyone and to all my friends, both local and international, who did everything to support and help me to be released," Dara said.
Dara received a hero award last year from US Secretary of State Antony Blinken, recognising his work exposing the existence of massive scam compounds staffed mostly by trafficked workers in Cambodia, and the US embassy had called for his release.
Washington's top aid official, Samantha Power, who announced more than $US38 million ($A57 million) in new US funding for projects in Cambodia during a visit this week, said she had met with Dara's family and raised his case with Prime Minister Hun Manet.
Power, the US Agency for International Development's administrator, welcomed his release on bail on Thursday.
"We continue to seek a quick and fair resolution to his ordeal," she added in a post on X.
— PEN International (@pen_int) #Cambodia: We welcome journalist Mech Dara's release on bail after he was unjustly detained on incitement charges. We call for all remaining charges to be dropped immediately. For further updates, see our statement⬇️https://t.co/rTOiYA5OBhOctober 24, 2024
On Wednesday, Cambodia's information minister shared with journalists a video of Dara wearing prison garb and apologising.
It was accompanied by images of a handwritten three-page letter the minister said was from the journalist.
"In all the messages that I posted, I conveyed false information that affected the leaders and the country's reputation. I sincerely apologise for my mistakes and promise to stop sharing such harmful content," Dara said in the video.
Rights groups say press freedom and democracy have been backsliding in Cambodia for many years.
