Helen Gym is no stranger to speaking before elected officials - sometimes rather loudly. Now, she is vying for a seat at their table.

Gym, a Democrat, announced her candidacy for a City Council at-large seat at a lively rally Monday at the Ethical Society on Rittenhouse Square, where she focused mostly on education.

A former elementary-school teacher, she has become a fiery advocate for public education funding and a frequent critic of city policies surrounding it.

Gym, 47, the mother of three children in Philadelphia public magnet schools, entered the race with the endorsement of the Philadelphia Federation of Teachers, which has pledged to donate the maximum $11,500.

"We will support her campaign with the same energy and commitment that she has shown when it comes to high-quality education in Philadelphia," the union's president, Jerry Jordan, said at Monday's announcement.

Gym's children introduced her to a cheering crowd of about 200 following comments from the Rev. Mark Tyler of Mother Bethel A.M.E. Church. In a city without an elected school board, "the next best thing is putting Helen Gym on City Council," Tyler said.

Gym joined a growing list of Democratic at-large candidates hoping to take one of five seats up for grabs, including the one vacated by James F. Kenney.

The Democratic incumbents are Blondell Reynolds Brown, William K. Greenlee, W. Wilson Goode Jr., and Ed Neilson. Republican at-large Councilmen David Oh and Dennis O'Brien are also running for reelection.

In addition to Gym, the roster of nonincumbent Democratic candidates includes Paul Steinke, former manager of Reading Terminal Market; former Councilman Frank Rizzo Jr.; Isaiah Thomas, a professor and former candidate; Sherrie Cohen, a lawyer with the Tenant Union Representative Network; Tom Wyatt, a partner at the Dilworth Paxson law firm; and Jenne Ayers, a Yale University law student and daughter of Lloyd Ayers, former fire commissioner.

Gym, a University of Pennsylvania graduate, was named one of the 75 most influential people in the city by  Philadelphia Magazine in 2014. She founded Parents United for Public Education, which seeks more funding and resources for public schools, and is on the board of the advocacy group Asian Americans United.

Known for her fervid and sometimes combative demeanor, Gym said, "People sometimes ask me if I'm angry," eliciting chuckles from the crowd. She said that when it comes to poverty and the state of public schools, "if you are not angry, if you are not outraged, then, as the saying goes, you're not paying attention."

215-854-5506 @juliaterruso