Seymour "Sy" Schuster was a relentless advocate for diverse students and faculty at Carleton College in Northfield, where he was an accomplished math professor, mentor and social justice activist.

Schuster was a friend and campaign adviser to the late U.S. Sen. Paul Wellstone, who had been a fellow Carleton professor. He was active in Rice County politics and served on the State Central Committee of the DFL Party.

Schuster, 94, died Oct. 28, just days after contracting COVID-19.

"I couldn't have done what I did at Carlton without having Sy as a warrior for justice," said the Rev. Jewelnel Davis, university chaplain and associate provost at Columbia University in New York, who collaborated with Schuster in the 1980s and 1990s.

"There weren't many African American women working as chaplains in the country," she recalled. "Sy was not only there in terms of supporting my work in justice, but I always knew I could count on him personally."

Schuster was born in the Bronx in New York City in 1926, the son of Oscar and Goldie Schuster. He enlisted in the U.S. Navy Reserve when he was 18, and later pursued academic studies, earning a Ph.D. from Pennsylvania State University.

In 1958, Schuster and his wife, Marilyn, moved to Northfield to begin teaching at Carleton, where he spent most of his career until retiring in 1994. He left Carleton for just five years, starting in 1963, to lead the College Geometry Project, a series of films to help elementary and secondary math teachers improve their instruction. He was an enthusiastic and popular teacher, and over the years also published several books and more than 30 scholarly papers.

Dave Appleyard said he was a freshman majoring in history when he took Schuster's first calculus class in 1958. Inspired, Appleyard switched his major to mathematics with a goal of teaching high school. Schuster urged him to go for a Ph.D., and Appleyard did. Coming full circle, he wound up teaching in Carleton's math department with his mentor, too.

"Sy had a huge impact on my life and on so many others," said Appleyard, now retired. "More than 70 students have signed his [memorial] page on Carleton's website. One person wrote that he 'altered the paths of all those fortunate enough to be with him.' That pretty much sums him up."

Eve Schuster remembers that her father's activism was part of family life, whether it was protesting the Vietnam War or taking on the girls' dress code at Northfield public schools. Girls were supposed to wear skirts or dresses. Her parents sent her to school in pants.

"It was embarrassing," she laughed. "But within a year, the dress code was changed."

Paul Schuster said his father's passion for social justice stemmed from his own experience with discrimination as a Jew. That led him to involvement in countless issues related to discrimination, racism and human rights, he said. He also supported diversity in the broadest sense of the word.

When then-professor Wellstone was denied tenure at Carleton, Schuster was a faculty leader in the 1974 campaign that successfully reversed that, said his son.

Schuster enjoyed tennis, wilderness canoeing and backpacking, as well as monthly poker games and annual fishing trips with longtime Carleton friends, Paul Schuster said.

To honor Schuster's contributions, the Carleton College Math and Statistics Department has created a Sy Schuster Award for Leadership in Diversity and Inclusion.

Schuster is survived by son Paul of St. Paul, daughter Eve of Brooklyn Center, brother Abe Schuster of West Dover, Vt., and two grandchildren. An online memorial service is scheduled for Nov. 29.