A self-described 'social justice activist' who was front and centre during a raucous 2009 protest in the House of Commons gallery now hopes to snag a seat in the Chamber itself.

Early Monday, longtime New Democrat supporter Joe Cressy announced that he will seek the NDP nomination to replace Olivia Chow as MP in the Toronto riding of Trinity-Spadina.

Chow resigned her seat last week to run for mayor of Toronto.

In 2009, Cressy was front and centre as several hundred youth protesters filled the public gallery to show their support for an NDP-backed climate change bill that would have set strict standards for emissions reduction.

Shortly after question period got underway, a small number of activists — including, according to multiple reportrs, Cressy himself — began chanting slogans.

Within minutes, Hill security had cleared the gallery, and arrested several protesters.

During the ensuing media circus, Cressy wound up acting as an unofficial spokesperson for the group.

Meanwhile, the NDP issued a statement denying any involvement with the stunt, despite Cressy's ties to the party.

Worked for Chow, Dewar

"Joe Cressy is an environment activist, and as many environment activists, he joined the NDP because it is the best political vehicle to make progress on environmental issues," the statement noted.

"This does not preclude the fact that, as environmental activists, they do their own thing with other groups that are not affiliated [with] the NDP."

According to media reports, a New Democrat MP had arranged passes for the protesters, and Cressy was a member of Ottawa Centre MP Paul Dewar's riding association at the time.

Cressy, who has now stepped down as president of the party's riding association in Trinity-Spadina, served as Chow's campaign chair in the 2011 federal election and is a member of the NDP federal council.

He also worked on Dewar's 2012 leadership campaign.

If elected, Cressy says he will build on Chow's legacy. He says he will stress a progressive urban agenda and environmental and social justice at home and abroad.

"All my life I've been driven by a desire to make real change in people’s lives," he said in the news release announcing his candidacy.

"I've led literacy programs in fly-in Aboriginal reserves in Northern Ontario, worked with anti-poverty, human rights, and HIV and AIDS groups in sub-Saharan Africa, and worked on environmental issues right across Canada."

With files from The Canadian Press