Chicago Teachers Union (CTU) President Karen Lewis holds a press conference after CTU delegates voted to end their strike on September 18, 2012 in Chicago, Illinois. More than 26,000 Chicago Public school teachers and support staff walked off the job on September 10 after the union failed to reach an agreement with the city on compensation, benefits and job security. With about 350,000 students, the Chicago school district is the third largest in the United States. Students will return to school tomorrow. (Photo by Scott Olson/Getty Images)

Who is Karen Lewis?

Karen Lewis, 59, is the fiery president of the 30,000 member Chicago Teachers Union, a position she has held since 2010. Prior to this high-profile role, Lewis was a dedicated high school chemistry teacher who taught in the city’s public schools for 22 years. She considered retiring in 2009, but support from teachers, keen for a strong leader, encouraged her to run for union president.

Lewis is a product of Chicago Public Schools (CPS), until accepting early admission at Mount Holyoke College. She later transferred to Dartmouth College, where she earned the distinction of being the only African-American female in her 1974 graduating class.

The feisty Chicago native comes from a family of educators — her father, mother and husband, John Lewis, who is now retired, all were CPS teachers. She has been a member of the union since 1988.

Why is she on theGrio’s 100?

Lewis was at the center of the Chicago teachers’ strike, which put the national spotlight back on urban public schools. Overnight, she became a national figure, a cause célèbre for the rights of educators and an outspoken advocate against the privatization of public education.

Described by those who know her as unabashedly oppositional, Lewis led the walkout on September 10, 2012. It followed more than a year of slow, fraught negotiations between the union and Mayor Rahm Emanuel’s administration.

The dispute, in the third-largest school system in the country, left some 350,000 children stranded. Among the major issues the teachers were negotiating were the length of the school day, evaluations being tied to performance and concerns about potential job losses.

At the end of the eight-day strike, the union won some important concessions limiting the mayor’s sweeping reform program, which included student test scores having less of a role in teacher evaluations than the city had originally planned.

The dispute was a public relations dream for the union and a galvanizing event for teachers across America.

What’s next for Lewis?

Lewis’s term expires this year and her position is up for re-election this coming May. Whether she is re-elected remains to be seen but so far Lewis has certainly made her mark.

Follow Karen Lewis on Twitter via Chicago Teacher Union at @CTULocal1