Gary Laison, 84, of Philadelphia, a longtime popular math professor at St. Joseph’s and Lehigh Universities, a passionate political activist, and a Renaissance man, died Wednesday, Aug. 18, of Alzheimer’s disease at home.

Dr. Laison taught math at St. Joseph’s for 35 years, and at Lehigh for 16, and was head of the computer science program at St. Joe’s for many years. He wrote papers on mathematical topics, two with his wife of 59 years, Diane, and retired from St. Joseph’s in 2017.

He was a well-liked professor, and cited by one colleague at St. Joseph’s as a defining influence in her academic life. In one online review, a St. Joseph’s student called him “probably one of the most brilliant people I’ve ever met.” Another wrote that he was a “genius, and a sweetheart.”

He overcame a lifelong stutter and was a “brilliant, kind, and caring person,” his wife said. “He took people seriously and showed them respect. I don’t think he realized how much he was admired and loved.”

Dr. Laison was passionate about human rights and social and racial justice. He marched and rallied against war and was active with the Fair Play for Cuba Committee, the local Independent Citizens Committee, the NAACP, and other groups.

In the 1960s, he was arrested for protesting the invasion of Cuba and the Vietnam War. He helped organize national boycotts of Woolworth stores with segregated lunch counters, participated in the 1963 March on Washington that advocated for civil and economic rights for Black Americans, and was part of the Occupy Philadelphia protests near City Hall in 2011.

He debated social and political issues with his wife and, after follow-up research, would often change his views.

“That was a sign of his integrity,” his wife said.

Born Dec. 9, 1936, Dr. Laison graduated from Overbrook High School and earned bachelor’s and master’s degrees in math and a doctorate in math at the University of Pennsylvania. He met Diane Splaver in 1957 when they were both math students at Penn, and they married in 1962.

She went on to become a math professor at Temple University, and their son, Josh, is a math professor at Willamette University in Salem, Ore. Dr. Laison first taught at Lehigh, then joined St. Joseph’s in 1982.

“He was caring and generous, and shared his love of academics and world matters with me,” said his son.

Young people were drawn to Dr. Laison because of his kindness, easygoing demeanor, and intelligence. He was a voracious reader who collected thousands of books about literature, science, history, music, art, and culture.

His great loves were math and poetry, and he went so far as to learn Homeric Greek, to better comprehend the works of Homer; German, to more fully understand Rainer Maria Rilke and Bertolt Brecht; and Spanish, to completely absorb the writing of Gabriel García Márquez.

He wrote a 21-chapter manuscript called Mathematics, Culture, and Society the family hopes to publish soon.

“He loved language,” his wife said. “We were a great team together.”

In addition to his wife and son, Dr. Laison is survived by a granddaughter, sister, and other relatives.

Services were Sept. 11.