Ernesto Yeboah was charged with failing to contact the authorities before organizing a Black Lives Matter vigil last week, police say.
He says the Economics Fighters League is considering taking legal action against the police and has hired two lawyers.
Scores of demonstrators chanted "Free Ernesto!" outside the police station where he was being held.
The incident escalated when armed officers rushed to the scene and fired shots in the air, witnesses said.
Gbontwi Anyetei, a demonstrator at the police station, said the crowd broke out in disarray.
"I was shocked and I was scared. Everyone just took off running," Anyetei said.
There are no reports of injuries sustained from the shots fired, but another protester, Kuukua Eshun, severely wounded her elbow after she fell while attempting to flee the scene.
"All we needed was for them to give us notice to leave, but instead they just came out and started shooting. I thought I was going to die. I am still traumatized," she said.
Yeboah, who is the leader of the Economic Fighters League, described as a non-partisan movement, said his intention was for the June 8 event to be a peaceful sit-in.
However, police say he violated the country's Public Order Act
, which states that "any person who desires to hold any special event shall notify the police."
Yeboah was granted bail at GH¢100,000 ($17,000) and released before being detained again shortly after his preliminary hearing on Thursday.
He was released a day later and his next court appearance is scheduled for July 7.
From protest to clashes
Yeboah was in the middle of giving a speech on social empowerment at the vigil when a swarm of police officers surrounded the political activist and whisked him away.
Angry protesters intervened, prompting clashes between authorities and the crowd.
"I could not believe what was happening. It is not up to the police to approve a vigil," Yeboah told CNN.
"No one in power should be above the Constitution," which states that "all persons shall have the right to...freedom of assembly including freedom to take part in processions and demonstrations."
He says days before the event, he sent a letter to the Inspector General of Police and copied the Greater Accra Regional Police Commander, the Ministry of the Interior, and the Ministry of Foreign Affairs informing them he was arranging a Black Lives Matter vigil. He received no response, he said.
But the superintendent of the Ghana Police Service, who also serves as the director of Police Public Affairs, refutes those claims.
"We have no records of a notice indicating he was organizing the protest," Sheilla Kessie Abayie-Buckman told CNN
"The police must receive notice of events like these in order to provide the necessary protection for demonstrators."
She continued: "What he organized was in flagrant disregard to the president's directive to enforce social distancing in the era of Covid-19."
Yeboah said he was unaware of the charges brought against him until hours after he was detained on Saturday evening.
Abayie-Buckman says the firing of shots was a necessary measure to disperse the protesters, who were putting themselves and others at risk of contracting the coronavirus.
"We applied the needed force so that peace and sanity could prevail," she added.
"We are ready to fight," said Yeboah. "What they did was unconstitutional and I will always fight to get the justice black lives deserve."