Toni Preckwinkle — longtime history teacher, Chicago alderman, president of the Cook County Board — had her passion for politics and public service sparked as a top student at St. Paul's former Washington High School.

Tall and serious, with a "wonderful" smile, the former Toni Reed was memorable most of all for her brains, said classmate Renee Ransom.

"When you're growing up, do you remember meeting someone and saying: 'God, she's really smart?" Ransom said. "That's what I remember most about Toni."

If Preckwinkle can win a runoff contest April 2, she will be memorable for something else: becoming the first black woman elected mayor of Chicago. Lori Lightfoot, a former federal prosecutor, and Preckwinkle finished atop a 14-candidate slate of contenders to lead the Windy City. If Lightfoot wins, she also would be the first black female mayor in Chicago history — as well as the city's first openly gay mayor.

Ransom wasn't the only classmate to deem Preckwinkle plenty smart. In the school's 1965 yearbook, Preckwinkle and fellow senior Geoff Olson were voted "Most Intelligent."

Her father, Samuel A. Reed, was past president of the St. Paul NAACP and an outspoken black community activist in the early 1940s. In the late 1960s, he was active in several neighborhood groups that were critical of several urban renewal projects in the Summit-University neighborhood. He also served on the Metropolitan Council. Reed died of cancer in 1987.

Preckwinkle was an active and involved student at Washington. She was president of the school's Girl's Athletic Association in the days before girls were allowed to participate in interscholastic sports. She also was a member of the school's World Affairs Club.

She was featured in an April 1965 story in the Minneapolis Tribune after she was named a National Achievement Scholar, a program for high-achieving black students administered by the National Merit Scholarship Corp. In the story, she said that besides her studies and sports, she was interested in world affairs and civil rights.

"I think civil rights is everyone's responsibility," she told the Tribune.

Inspired by St. Paul teacher

It was about this time that she first became active in politics, volunteering for her high school social studies teacher's campaign for the St. Paul City Council. The late Katie McWatt was the first black woman to run for City Council, and although she did not win, Preckwinkle said on her website that "Katie's strength and determination really inspired me, and it was because of that campaign that I would eventually dedicate my life to public service."

Ransom, who went on to a long career as a guidance counselor in the St. Paul Public Schools, said that she and Preckwinkle were among "maybe 12" black students at Washington at the time. Despite going to school at the height of the civil rights movement, Ransom doesn't remember any racial unrest at the school in the heart of St. Paul's Rice Street neighborhood.

Preckwinkle finished in the top 20 percent of her class and went on to earn bachelor's and master's degrees from the University of Chicago. Preckwinkle taught history in Chicago area schools for a decade, before winning a seat on the City Council (on her third try) as Fourth Ward alderman in 1991.

In 2011, she became president of the Cook County Board, the first woman to win that job.

Now chairwoman of the Cook County Democratic Party, with decades spent as a progressive in Chicago politics, Preckwinkle, 71, once again is trying to distinguish herself — this time against a political newcomer — in the contest to lead the nation's third-largest city.

James Walsh • 612-673-7428

Correction: Previous versions of this article misstated that Samuel Reed was the first black member of the Metropolitan Council.