Mary J. Armstrong, an educator and longtime president of the American Federation of Teachers St. Louis, Local 420, has died after struggling with a chronic illness for several years, family members said.
“Mary was a fierce champion for St. Louis Public Schools,” said Kathy Conley-Jones, Armstrong’s lifelong, self-described “sista/friend.”
“Mary’s negotiating skills; her not backing down but also understanding that it took both sides was beyond anything I’ve ever seen,” Conley-Jones continued. “As it relates to public schools, everything Mary did came from her heart.”
Armstrong became president of Local 420 in 2003 and led the union until retiring from education in July 2017 after a 30-year career. She took over as the district entered one of the most turbulent periods in its history.
Around the same time, former Mayor Francis Slay and a newly formed seven-member school board hired turnaround firm Alvarez & Marsal. William Roberti, a former clothing store executive, was named interim superintendent. To close a massive budget gap, the firm closed schools, eliminated jobs, privatized services and angered many teachers, parents and community members.
Armstrong quickly took issue with the firm’s approach.
“They are a reputable firm, but this is their first time dealing with a public entity,” Armstrong told reporters. “It just seems like everything has been done behind closed doors, and then, bam! This is what it’s going to be.”
Former SLPS Superintendent Dr. Kelvin Adams said his relationship with Armstrong often resembled another kind of union.
“I would always say Mary and I were in a marriage and, like sometimes in a marriage, you have to sleep on the sofa,” Adams said with a laugh. “But we both fought really hard to do what’s best for this district.”
Continuing the marriage analogy, Adams said there were times when either one of them walked away from the negotiating table, but they always came back because of their shared commitment to the children they served.
Armstrong also used the pages of The St. Louis American to challenge city leaders. As Slay pushed to expand charter schools, she questioned his definition of progress in a 2007 commentary.
“It is apparent that Slay’s energy and resources have been devoted to obtaining the authority to force more charter schools on St. Louis,” Armstrong wrote. “The mayor’s misguided assurances that more charter schools will deliver improved student achievement are conspicuously ignorant of facts that contradict his claims.”
“There was something about Mary J. Armstrong,” said Dr. Nicolé Williams Freeman, a friend and former SLPS deputy superintendent.
“There are people whose accomplishments can be measured by the offices they held… then there are people whose greatest achievements are found in the lives they touched and the hope they inspired. Mary J. Armstrong was that kind of leader.”
“She possessed the rare ability to bring people together around a common purpose,” Williams Freeman continued. “Whether she was advocating for teachers, mentoring new leaders, or engaging in difficult conversations about public education, she never lost sight of the reason we were there.”
Conley-Jones said Armstrong died much as she lived — surrounded by family, friends and joy.
“Mary was with her family and girlfriends who played card games and board games every other week,” Conley-Jones recalled. “She was in great spirits, had eaten a wonderful meal, wished everyone good night, went to bed around 1 a.m., and she passed away at 1:48 p.m.”
Armstrong is survived by her son, Eric L. Armstrong, and grandson, Eric L. Armstrong.
A Celebration of Life will be held Thursday, July 30, 2026, from 9:30 a.m. to 12:30 p.m. at Austin Layne Mortuary. An Alpha Delta Chapter event will precede the service.
Sylvester Brown Jr. is the Deaconess Foundation Community Advocacy Fellow.