Margaret Blackshere went from teaching kindergarten in a downstate classroom to making history as the first woman to lead the Illinois AFL-CIO and helping lead Democrats to victory across the state.

“She was an amazing woman not just because she was the first woman to lead the AFL-CIO, but because she had such a commitment to working people in and out of unions,” said Barbara Flynn Currie, former majority leader in the Illinois House. “She was able to bridge gaps and made sure that people in the union stuck together, stayed together and stayed strong.”

Ms. Blackshere died Saturday. She was 78.

A former kindergarten teacher in downstate Madison, she worked her way up the ranks of the labor movement. She served as a president of Madison Federation of Teachers Local 743 and eventually was a statewide vice president of the Illinois Federation of Teachers.

She was elected secretary-treasurer of the Illinois AFL-CIO in 1993, and served as president of the million-member labor organization from 2000 to 2007 after winning its first ever contested election for president. She threw her full support and political muscle behind countless Democrats, helping Dan Hynes win election as state comptroller and Barack Obama as president of the United States.

“She wouldn’t just tell you who to call, but would often make calls for you and make introductions and draw you a roadmap to how to win statewide in Illinois,” Hynes said.

Democrats courted Ms. Blackshere for her expertise, her support and her friendship. She was a delegate to the Democratic National Convention and a member of the Democratic National Committee.

“Margaret Blackshere had the caring heart of a downstate teacher and the fierce spirit of an advocate fighting for justice in classrooms and workplaces across Illinois,” U.S. Sen.Dick Durbin said. “She made history as the first woman to serve as president of the Illinois AFL-CIO and her legion of friends, like Loretta and me, will miss her great humor and her willingness to always wish others well unless they were playing her beloved St. Louis Cardinals.”

Currie said her friend was someone who had “such a flair and commitment to the issues that mattered to working people” and that the former labor leader was “one of a kind.”

Though the two were connected through politics, Currie says they got together with others every week to watch “The West Wing,” often eating Thai food as they caught up with the political drama when it was still airing.

With Ms. Blackshere at the helm, the labor organization enjoyed legislative victories as well, such as winning increases in the state minimum wage. Dennis Gannon, a former president of the Chicago Federation of Labor, credited her with helping land pro-labor individuals on state boards and commissions when Ms. Blackshere announced she was stepping down at Illinois AFL-CIO president.

Cook County Board President Toni Preckwinkle said she identified with Ms. Blackshere because of their shared teaching backgrounds, but said she got to know her mainly through political campaigns.

“She was a tough and effective labor leader,” Preckwinkle said. “She was also fun — she had a great sense of humor. ... She was a great lady, I liked her a lot.”

In a tweet, Gov. J.B. Pritzker said Ms. Blackshere “dedicated her life to fighting for Illinois teachers and social justice for all.”

“She was a trailblazer and an organizer, a loving mother and grandmother, and a role model for all of us,” the governor said in the tweet. “The entire state mourns her passing and keeps her family in our thoughts.”

Hynes, a former state comptroller who is now one of Pritzker’s deputy governors, said Ms. Blackshere was “instrumental” in his first election as comptroller and treated him like a son when he was running for office. She introduced him to labor leaders around the state to help him garner the votes needed to win statewide.

“She was a great organizer, a committed teacher and someone who cared about the state of Illinois,” Hynes said.

House Speaker Mike Madigan and his wife, Shirley, issued a statement paying tribute to “Margaret and her fierce spirit.”

“Margaret Blackshere’s impact on the hard-working men and women of Illinois will be felt for generations to come,” they said. “As the first woman to serve as president of the Illinois AFL-CIO, Margaret created a seat at the table for female workers and always fought for their best interests. She had a passion for building bridges and uniting people around common goals with a spark and an energy that was unmatched.”

The Illinois AFL-CIO issued a statement saying it “mourns the passing” of Ms. Blackshere, “a fearless leader for economic and social justice from the halls of the State Capitol to the picket lines and shop floors up and down our state. She will be deeply missed by our organization, the labor movement and working families throughout Illinois.”

Bob Reiter, president of the Chicago Federation of Labor, said in a statement that Ms. Blackshere was “a giant of the Illinois labor movement and a crucial partner of the Chicago Federation of Labor. Working men and women across Illinois will feel the impact of her work for generations to come. We mourn her passing and our thoughts are with her family at this time.”

The Chicago Federation of Labor is one of the organized labor groups that has an ownership stake in the Chicago Sun-Times.

Illinois Federation of Teachers President Dan Montgomery said: “From her start organizing teachers in Madison, Ill., to her leadership at the state and national levels, Margaret’s efforts to make our state and country better and fairer for everyone were inspirational and quite necessary. She was a tireless advocate for working people and a shining example of what a union leader can be.”

Beyond leading the AFL-CIO, Currie said Ms. Blackshere enjoyed baseball and other hobbies.

“She was down to earth, she was a real person and her passing is the end of a very important era in Illinois labor history,” Currie said. “She was a great woman — we’re sorry to lose her.”

Survivors include two sons, Michael and Thomas; a sister, Patricia Smith, and four grandchildren. Visitation will be held from 1 to 9 p.m. Wednesday at Cooney Funeral Home, 625 Busse Highway in Park Ridge. The funeral is scheduled for 11 a.m. Thursday at St. Juliana Roman Catholic Church, 7200 N. Osceola Ave.