She served as a physician in the United States Navy during World War II.

She was a obstetrician and gynecologist on the faculty of the Woman's Medical College of Pennsylvania.

[4] Her great-grandfather, John Pitkin Norton, was a chemistry professor at Yale University.

[7][9] She served as a physician in the United States Navy during World War II,[10] in charge of the women's branch of the hospital at the Marine depot at Parris Island.

[5] Drexel University awards an annual Mary Dewitt Pettit Fellowship, to support the research or special projects of junior faculty members in the College of Medicine.