Anne Smedinghoff graduated from Fenwick High School in Oak Park in 2005 and went on to become a U.S. foreign service officer.
She and three American soldiers were killed Saturday in Afghanistan when the Taliban attacked a convoy in which they were traveling.
In a memorial service at Fenwick Tuesday, Smedinghoff's former Spanish teacher, Irene Drago, described her 25-year-old former pupil as "so focused and determined to unravel the big problems," the Chicago Tribune reported Wednesday.
The Rev. Richard Peddicord, president of the Catholic high school, said everyone "belongs to one human family. And she believed that and lived that."
Smedinghoff spoke to several classes at Fenwick during a family visit in December. During the memorial, faculty members urged students to continue her example of helping people.
"It's now up to us to validate Anne's life," said Gerald Lordan, a social studies teacher.