Hallinan was born in New York City, the daughter of Irish immigrants.
She received an undergraduate degree in mathematics from Marymount College, and she was a nun and math teacher at a Catholic high school before attending graduate school.
She earned a master's degree from Notre Dame and a doctorate in sociology and education from the University of Chicago.
Hallinan separated from her religious order while pursuing her graduate education.
[2] In 1984, Hallinan became the second female to receive a named chair appointment at Notre Dame.