Nashville's Metro Council unanimously voted to reinstate Justin Jones, the Tennessee House representative who was ousted last week for taking part in a gun control rally.
Jones will serve as an interim legislator until a special election is called.
"This is about people power. It shows that people power is the ultimate power, not the decision of [House Speaker] Cameron Sexton, but the decision of the people," Jones said after the hearing on Monday.
Nashville Vice Mayor Jim Shulman, the council's president, told ABC News that members quickly scheduled the meeting following Thursday's vote by the Republican-led statehouse to expel Jones and Justin J. Pearson for allegedly violating the chamber's rules of decorum by participating in the March 30 protest.
State Rep. Gloria Johnson, who also took part in the protest that was prompted by the March 27 mass shooting at the Covenant School, was also subjected to an expulsion vote, but not enough members supported it.
The meeting on Monday was packed with Jones' supporters who made their voices heard, as council members weighed their decision on the future of Jones' seat.
Councilwoman Delishia Porterfield, who nominated Jones during the meeting, spoke out against the legislature's move to oust him and Pearson, calling their vote a "miscarriage of justice and egregious assault on our democracy."
"With this vote to reinstate Representative Jones we are restoring the voice [of] 70,000 people of District 52," she said.
The crowd let out a huge cheer when the vote came through after nearly 12 minutes.
"With this vote, we will send a strong message to our state government and across the country that we will not tolerate threats to our democracy," Porterfield said.
Jones thanked his supporters outside the council chambers and celebrated his reinstatement.
"Justice is not about one person, it is about the movement of people," he said.
Jones, 27, ran for office last year for the open house seat in Tennessee's 52nd District, which includes Nashville. He had no opponents in the general election.
Jones was back in the Capitol chambers later Monday evening and again vowed to be a voice for his constituents.
"I want to thank you all, not for what you did, but for awakening the people of this state, particularly the young people," Jones said, to cheers.
Johnson walked with Jones as he entered the chambers.
Pearson was in the stands watching Jones' speech and raised his fist in the air for support
"The voice of the people are back in the Peoples's [sic] House!" Pearson tweeted.
Jones later tweeted: "In the end, the people of Tennessee made the ultimate choice of courage and hope. Thank you to the thousands who came to the people's house today to show the nation that we will not yield to authoritarian attacks on our democracy. Our fight is not over."