Gret P. Gentile, 81, of Philadelphia, a physical education teacher and lifelong peace activist, died Monday, May 10, of breast cancer at her sister’s home in Schuylkill Haven.

Ms. Gentile worked as a teacher, UPS driver, and freelance helper. But her true calling was her passion for peace and understanding among people, which took her around the country and as far as Russia.

“She was definitely a free spirit,” said her daughter, Emjae Melinda Jeanne. Her true priorities were “peace activism, bringing people together, breaking barriers, and forging peace and connections in the world.”

Raised in Lansdowne, she was the third of four children born to Arthur and Myrtle Cunningham Gentile. She graduated from Temple University with a bachelor’s degree in education. And while she was there, she coached a men’s intramural basketball team at Temple, which was chronicled in the Philadelphia Bulletin at the time.

After college, she married John P. Simpson Jr. and they moved to Virginia, where Simpson entered the seminary to become an Episcopalian minister. Ms. Gentile worked as a physical education teacher in Virginia and also in Kansas, where she and her husband later moved. The couple also became active in the peace movement, protesting the Vietnam War. They moved to the Philadelphia area in 1977 but divorced in 1986. Simpson died in 2018. The couple had three children.

After the Vietnam War, Ms. Gentile turned her activism toward protesting nuclear arms, her daughter said.

A music lover, she sang with the Philadelphia Chorus for 25 years and played oboe for various local companies.

In the 1970s, she got a job driving for UPS in Philadelphia — unusual for a woman at that time. But she quit after a promotion to manager, her daughter said, and became a freelance helper — house cleaner, driver, just about anything that would enable her to support herself and continue her activism.

“What she would say is she would do anything that she considered moral, safe, and fun,” Jeanne said.

Among her major accomplishments was participating in the 1986 Great Peace March for Global Nuclear Disarmament from Los Angeles to Washington, D.C., and then the American Soviet Walk between then-Leningrad and Moscow in 1987.

It was an experience she would reference often in guest lectures on peace activism at schools and churches.

“She was very engaged in world events and … she always talked to us about being nonjudgmental,” said Jeanne. “She always role-modeled accepting everybody.”

It was not unusual for her to invite a stranger into her home, including during the holidays to participate in her family’s gatherings.

“She was vivacious. She was gregarious. She was lighthearted and she was jovial,” her daughter said. “She could relate to everybody and just wanting to make the human connection, the spiritual and emotional connection, because for Gret, what mattered was who you were, how you viewed the world, and how you moved through the world.”

“‘We’re one family’ was her motto,” Jeanne said.

In addition to her daughter, Ms. Gentile is survived by her sons, Geoffrey S. Simpson and Eric J. Simpson; one sister; and other relatives. Her other sister, brother, and parents died earlier.

A celebration of Ms. Gentile’s life was held Saturday, May 29.

Donations in her memory can be made to the Philadelphia Chorus, P.O. Box 42735, Philadelphia, Pa., 19101.