The woman, whose identity remains unknown, has drawn comparisons to the so-called Nubian Queen, a Sudanese woman whose image went viral after she was pictured directing protests that ultimately led to the overthrow of long-time dictator Omar Bashir in April.
Lebanese media reports said the incident happened Thursday evening when the convoy of Education Minister Akram Chehayeb was confronted by demonstrators in central Beirut.
One of the minister's bodyguards got out of the car and fired an assault rifle in the air, sparking an angry reaction from the crowd.
In a scuffle, as another bodyguard steps back while holding a gun in the air, the woman leans back and fires a left-footed side kick into his groin.
The man, seemingly shocked, staggers forward.
The video has been shared thousands of times online and highlighted as a symbol of two days of demonstrations against corruption and proposed tax hikes.
Social media users praised the actions of the female protester, describing it as brave, courageous and fearless.
"When they steal your money, corrupt your country, and pull a machine gun at you -- you give them a quick kick in the groin!" one user said on Twitter.
"Our women don't just kick ass, they kick men with guns," another said.
One blogger shared a stylised screen grab of the image, saying it should be called "Lebanon's Kick-their-Ass Revolution."
Demonstrators took to the streets Thursday evening for the largest protests in several years.
Many are calling for an overhaul of Lebanon's sectarian system and voicing contempt for their leaders.
At renewed protests Friday, demonstrators said the video made them determined to press on.
"I felt the anger in her and (her) just doing it, without anything else in her mind," Marina, 25, said.
"She was angry and she expressed it in the movement, not just by speaking. Usually a woman doesn't act (out physically)."
Jen, a 26-year-old who works in advertising, said: "I think all the women felt like somebody is representing them and somebody is fighting for them."
"It showed that women don't need a man to fight for them," she told AFP.
Hannah, 24, said the video inspired her to fight against a "patriarchal society".
"We shouldn't be afraid to hit this man, we shouldn't be afraid of them," she said. "It is time to show our strength."