Mary Daily Lacy, who taught at Bryn Mawr School for more than four decades and was a mentor to faculty members, died of sepsis June 30 at Sinai Hospital. She was 72 and lived in the Village of Cross Keys.

Born in Baltimore and raised on Springlake Way, she was the daughter of James J. Lacy Jr., an insurance executive, and Dorothy Callis Lacy, who worked in retail. She attended the School of the Cathedral and was a graduate of Maryvale Preparatory School in Brooklandville, where she played sports.

She attended Marymount University in Virginia, before receiving a bachelor’s degree from the University of Maryland, College Park, and a master’s degree from Towson University.

In 2023, she retired after 41 years at Bryn Mawr but worked another year as a part-time teacher.

Sue Sadler, Bryn Mawr head of school, said: “She was part of Bryn Mawr for 40 years. She’s the kind of teacher parents pray for for their children. She gave little people the time and space to be themselves. She taught them to be lifelong readers and curious learners.

“Better yet, she instilled kindness, respect and independence in their characters. She was also a colleague of the highest order,” Ms. Sadler said. “She brought her heart and her mind to her children.”

Hunter Hanley, a colleague, said: “Mary had experience and always let kids grow on their own and find their own way. She was a mentor to other teachers and trained new teachers for the first grade. She knew how to teach, there was no pretense with her. She knew right from wrong.

“She had a direct way — although she was not strict — and her students knew she meant business. She had sayings, ‘You get what you get and you don’t get upset’ or ‘Good readers reread.’

“She was true to herself. She said things the way they were. She was clear in her opinions and picked her words carefully.

“She stood up for people,” Ms. Hanley said. “She got to school half an hour early and there would be others waiting for her to tell a story. She had a great sense of humor and a great delivery.”

Her colleague recalled that Ms. Lacy did not like new technology.

“She had a love-hate relationship — mostly hate, with the digital world,” Ms. Hanley said.

“With Mary, the learning was almost like magic. The little ones could sing the alphabet, but couldn’t identify the letters,” said Beverly Grady, a fellow teacher and friend. “They’d soon be reading. Mary Lacy was meant to be a teacher.”

“She kept up with her students over the years — she remembered them and they remembered her,” Ms. Grady. “She could tell a story. She knew every children’s book out there. She often sent them as presents.”

Her sister, Loretta “Rett” Lacy of Baltimore, said: “She always kept me in line. She was the go-to person and told me how it is. Her advice was good. She was the boss.”

She won several awards for her teaching abilities including the school’s Lucy Eastwood Broadus Award in 1996.

She led a Bryn Mawr School initiative to fill the library at the Franciscan Center, a West 23rd Street social services agency.

Friends said she wrote her thank you cards in a clear cursive hand.

She was an AmeriCorps Vista volunteer in Tallahassee, Florida, and taught at Shrine of the Sacred Heart in Mount Washington early in her career.

A celebration of life will be held Sept. 7 at St. Ignatius Roman Catholic Church at 740 N. Calvert Street. The hour has not been set.

In addition to her sister, her survivors include her brother, James J. Lacy III, of Ocean City.